Synthesis and Absolute Configuration of Naturally Occurring Dactyloxene-B and -C

Natural (+)-dactyloxene-B (12) and -C (13) have been synthesized starting from (+)-trans-2, 5, 6-trimethyl-l-cyclohexene-l-carbaldehyde (1) which is shown to have the (5S, 6R)-configuration by chemical correlation with (+)-(2R, 3S, 6S)-2, 3, 6-trimethylcyclohexanone. The absolute configurations are therefore (2R, 5R, 9S, 10R) for (+)-dactyloxene-B and (2R, 5S, 9S, 10R) for (+)-dactyloxene-C.     

Synthesis and characterization of double hydrophilic block copolymers containing semi-rigid and flexible segments

3-Methyl-(E)-stilbene (3MSti) and 4-(diethylamino)-(E)-stilbene (DEASti) monomers are synthesized and polymerized separately with maleic anhydride (MAn) in a strictly alternating fashion using reversible addition-fragmentation chain transfer (RAFT) polymerization techniques. The optimal RAFT chain transfer agents (CTAs) for each copolymerization affect the reaction kinetics and CTA compatibilities. Psuedo-first order polymerization kinetics are demonstrated for the synthesis of poly((3-methyl-(E)-stilbene)-alt-maleic anhydride) (3MSti-alt-MAn) with a thiocarbonylthio CTA (methyl 2-(dodecylthiocarbonothioylthio)−2-methylpropionate, TTCMe). In contrast, a dithioester CTA (cumyl dithiobenzoate, CDB) controls the synthesis of poly((4-(diethylamino)-(E)-stilbene)-alt-maleic anhydride) (DEASti-alt-MAn) with pseudo-first order polymerization kinetics. DEASti-alt-MAn is chain extended with 4-acryloylmorpholine (ACMO) to synthesize diblock copolymers and subsequently converted to a double hydrophilic polyampholyte block copolymers (poly((4-(diethylamino)-(E)-stilbene)-alt-maleic acid))-b-acryloylmorpholine) (DEASti-alt-MA)-b-ACMO) via acid hydrolysis. The isoelectric point and dissociation behavior of these maleic acid-containing copolymers are determined using ζ-potential and acid–base titrations, respectively. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 219–227     

Structure and morphology development in syndiotactic polypropylene during isothermal crystallization and subsequent melting

Structure and morphology development during the isothermal crystallization and subsequent melting of syndiotactic polypropylene (sPP) was studied with differential scanning calorimetry (DSC), time‐resolved simultaneous small‐angle X‐ray scattering (SAXS), and wide‐angle X‐ray diffraction (WAXD) methods with synchrotron radiation. The morphology of sPP isothermally crystallized at 100 °C for 3 h was also characterized with transmission electron microscopy (TEM). Time‐ and temperature‐dependent parameters such as the long period (L), crystal lamellar thickness (l_c), amorphous layer thickness (l_a), scattering invariant (Q), crystallinity (X_c), lateral crystal sizes (L₂₀₀ and L₀₁₀), and unit cell dimensions (a and b) were extracted from the SAXS and WAXD data. Results indicate that the decreases in L and l_c with time are probably due to the formation of thinner crystal lamellae, and the decreases in a and b are due to crystal perfection. The changes in the morphological parameters (Q, X_c, L, and l_c) during subsequent melting exhibited a two‐stage process that was consistent with the multiple melting peaks observed in DSC. The two high‐temperature peaks can be attributed to the melting of primary lamellae (at lower temperatures) and recrystallized lamellae (at higher temperatures). An additional minor peak, located at the lowest temperature, was also visible and was related to the melting of thin and defective secondary lamellae. TEM results are consistent with the SAXS data, which supports the assignment of the larger value (l₁) from the correlation function analysis as l_c. WAXD showed that the thermal expansion was greater along the b axis than the a axis during melting. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2982–2995, 2001     

Synthesis and Asymmetric Enantioselective Addition of Chiral Polybinaphthyl and Polybinaphthol I.igands

Four chiral polymers P-1, P-2, P-3 and P-4 were synthesized by the polymerization of （S）-2,2＇-dioctoxy-1,1＇- binaphthyl-6,6＇-boronic acid （S-M-3） with （S）-6,6＇-dibromo-1,1＇-binaphthol （S-M-1）, （R）-6,6＇-dibromo-1,1＇- binaphthol （R-M-1）, （S）-3,3＇-diiodo-1,1＇-binaphthol （S-M-2） and （R）-3,3＇-diiodo-1,1＇-binaphthol （R-M-2） under Pd-catalyzed Suzuki reaction, respectively. All four polymers can show good solubility in some common solvents due to the nonplanarity of the polymers in the main chain backbone and flexible alkyl groups in the side chain. The analysis results indicate that specific rotation and circular dichroism （CD） spectral signals of the alternative S-S chiral polymers P-1 and P-3 are larger than those of S-R chiral polymers P-2 and P-4, but their UV-Vis and fluorescence spectra are almost similar. The results of asymmetric enantioselectivity of four polymers for diethylzinc addition to benzaldehyde indicate that catalytically active center is （R） or （S）-1, 1＇-binaphthol moieties.     

Preparation and Characterization of New C2‐ and C1‐Symmetric Nitrogen,Oxygen, Phosphorous,and Sulfur Derivatives and Analogs of TADDOL. Part II

TADDOL (=α,α,α′,α′‐Tetraaryl‐1,3‐dioxolane‐4,5‐dimethanol) and the corresponding dichloride are converted to TADDAMINs (=(4S,5S)‐2,2,N,N′‐tetramethyl‐α,α,α′,α′‐tetraphenyl‐1,3‐dioxolan‐4,5‐dimethanamines) (Scheme 2) and ureas, 12 – 15 , and to TADDOP derivatives with seven‐membered O? P? O ester rings (Schemes 3 and 4). Cl/P‐Replacement via the Michaelis? Arbuzov reaction (Scheme 7) on mono‐ and dichlorides, derived from TADDOL, are described. It was not possible to obtain phosphines with the P‐atom attached to the benzhydrylic C‐atom of the TADDOL skeleton (Schemes 6 and 7). The X‐ray crystal structures (Figs. 1 and 2) of ten of the more than 30 new TADDOL derivatives are discussed. Full experimental details are presented.     

Synthesis and investigation of antibacterial activities and carbonic anhydrase and acetyl cholinesterase inhibition profiles of novel 4,5-dihydropyrazol and pyrazolyl-thiazole derivatives containing methanoisoindol-1,3-dion unit

Novel 4,5-dihydropyrazole derivatives (3a–i), 3-(4-((3aR,4S,7R,7aS)-1,3-dioxo-3a,4,7,7a-tetrahydro-1H-4,7-methanoisoindol-2(3H)-yl)phenyl)-5-phenyl-4,5-dihydro-1H-pyrazole-1-carbothio amide, were obtained by the addition of thiosemicarbazide (2) to the chalcones (1a–i). The addition–cyclization of 2,4′-dibromoacetophenone (4) to pyrazole derivatives (3a–i) gave the new pyrazolyl-thiazole derivatives (5a–i), (3aR,4S,7R,7aS)-2-(4-(1-(4-(4-bromophenyl)thiazol-2-yl)-5-phenyl-4,5-dihydro-1H-pyrazol-3-yl)phenyl)-3a,4,7,7a-tetrahydro-1H-4,7-methanoisoindole-1,3(2H)-dione. Antibacterial and acetylcholinesterase (AChE) enzyme and human carbonic anhydrase (hCA) I, and II isoform inhibitory activities of the compounds 3a–i and 5a–i were investigated. Some of the compounds showed promising antibacterial activity. In addition, the hCA II and I were effectively inhibited by the lately synthesized derivatives, with K_i values in the range of 18.90?±?2.37 ?58.25?±?13.62?nM for hCA II and 5.72?±?0.98 ?37.67?±?5.54?nM for hCA I. Also, the K_i parameters of these compounds for AChE were obtained in the range of 25.47?±?11.11???255.74?±?82.20?nM. Also, acetazolamide, clinical molecule, was used as a CA standard inhibitor that showed K_i value of 70.55?±?12.30?nM against hCA II, and 67.17?±?9.1?nM against hCA I, and tacrine inhibited AChE showed K_i value of 263.67?±?91.95.     

Atomic and bond properties in functionalized esters and amides

The properties of various atomic groups of molecules containing a carbonyl unit (XCOY) consisting of an ester (Y=OR) or amide function (Y=NHR) in different molecular environments (X=H, Me, Et, OH, OMe, NH₂, NHMe, F, Cl), as well as their influence on the properties of the alkyl chain (R=C₈H₁₇) in the molecule, were analyzed by use of the theory of atoms in molecules (AIM). To this end, the main atomic and bond properties for each atom in 18 carbonyl compounds of the aforementioned types were determined on the basis of 6-31++G**//6-31G* wave functions. The properties of the C and O atoms in the carbonyl group, and those of their bonds, are directly related to the nature and electronegativity of the X substituent and to the character of the Y group. The nature of the C Y bond and the properties of the Y group are also dependent on the proximity of the X group. Based on the precision with which integrated properties were determined, assessed by L(Ω), the properties of the methylene groups of the R chain located in α and β with respect to Y are essentially dependent on the nature of Y and, to a lesser extent, on that of X. The methylene group in γ with respect to Y exhibits a dependence on the nature of the latter that vanishes in more distinct groups; therefore, the methylene in ε can be assimilated to one in an alkane. ©1999 John Wiley & Sons, Inc. J Comput Chem 20: 1444–1454, 1999     

Degradative ring opening of pyrido and pyrazino 3-benzenesulfonyloxyuracils and their conversion to condensed pyrazolones and triazolones

Ring opening, followed by an immediate Lossen rearrangement, of 3-benzenesulfonyloxypyrido[3,2-d, 3,4-d and 4,3-d]pyrimidine-2,4(1H,3H)diones with sodium methoxide in methanol furnished good yields of the methyl esters of 3-[2-(methoxycarbonyl)hydrazino]-2-, 3-[2-(methoxycarbonylhydrazino]-4- and 4-[2-(methoxycarbonyl)hydrazino]-3-pyridinecarboxylic acids, respectively. These hydrazino esters were cyclized to the corresponding pyridopyrazolones. However, the reaction of 3-benzenesulfonyloxypyrido[2,3-d]pyrimidine-2,4(1H,3H)dione with sodium methoxide produced 8-methoxycarbonyl-s-triazolo[4,5-a]pyridin-3(2H)one. In similar fashion, sodium methoxide converted 3-benzenesulfonyloxylumazine to 8-methoxycarbonyl-s-triazolo[4,3-a]pyrazin-3(2H)one.     

Synthesis of Phosphaformamidines and Phosphaformamidinates

A large‐scale synthetic route to a variety of phosphaformamidines and phosphaformamidinates, a type of derivative that was not accessible by the methods previously known for preparing phosphaamidines and phosphaamidinates, is reported. Thermally stable ethyl N‐arylformimidates 1 (ArN?CH(OEt), Ar=2,4,6‐(Me)₃Ph or 2,6‐(iPr)₂Ph) readily reacted with lithium dialkyl‐ and diarylphosphanides to afford the corresponding N‐aryl phosphaformamidines in 80 and 60 % yield, respectively, whereas with lithium (aryl)(silyl)phosphanide, the N‐aryl‐N‐silylphosphaformamidine (60 % yield) was obtained. Addition of primary lithium arylphosphanides to 1 followed by addition of a stoichiometric amount of nBuLi gave rise to the respective phosphaformamidinates (70–88 % yield). Methanolysis of the products afforded the N‐aryl‐N‐hydrogenophosphaformamidines (90–95 % yield). The solid‐state structure of one of the phosphaformamidinates is also presented.     

Photoinduced Interactions Between Oxidized and Reduced Lipoic Acid and Riboflavin (Vitamin B2)

As a powerful natural antioxidant, lipoic acid (LipSS) and its reduced form dihydrolipoic acid (DHLA) exert significant antioxidant activities in vivo and in vitro by deactivation of reactive oxygen and nitrogen species (ROS and RNS). In this study the riboflavin (RF, vitamin B₂) sensitized UVA and visible‐light irradiation of LipSS and DHLA was studied employing continuous irradiation, fluorescence spectroscopy, and laser flash photolysis (LFP). Our results indicate that LipSS and DHLA quench both the singlet state (¹RF*) and the triplet state (³RF*) of RF by electron transfer to produce the riboflavin semiquinone radical (RFH^.) and the radical cation of LipSS and DHLA, respectively. The radical cation of DHLA is rapidly deprotonated twice to yield a reducing species; the radical anion of LipSS (LipSS^.?). When D₂O was used as solvent, it was confirmed that the reaction of LipSS with ³RF* consists of a simple electron‐transfer step, while loss of hydrogen occurs in the case of DHLA oxidation. Due to the strong absorption of RFH^. and the riboflavin ground state, the absorption of the radical cation and the radical anion of LipSS can not be observed directly by LFP. N,N,N′,N′‐tetramethyl‐p‐phenylenediamine (TMPD) and N,N,N′,N′‐tetramethyl benzidine (TMB) were added as probes to the system. In the case of LipSS, the addition resulted in the formation of the radical cation of TMPD or TMB by quenching of the LipSS radical cation. If DHLA is the reducing substrate, no formation of probe radical cation is observed. This confirms that LipSS^.+ is produced by riboflavin photosensitization, and that there is no oxidizing species produced after DHLA oxidization.     

Syntheses and Crystal Structures of LaRhMg,CeRhMg, PrRhMg,and NdRhMg

New intermetallic rare earth compounds LaRhMg, CeRhMg, PrRhMg, and NdRhMg were prepared by reaction of the elements in sealed tantalum tubes in a high‐frequency furnace. The compounds were investigated by X‐ray diffraction both on powders and single crystals. LaRhMg crystallizes with the LaNiAl type structure, space group Pnma, Z = 8, a = 760.1(2), b = 419.92(8), c = 1702.6(2) pm, wR2 = 0.0482, 740 F² values and 38 variable parameters. The cerium compound adopts the ZrNiAl structure: P6¯2m, Z = 3, a = 752.3(1), c = 417.6(1) pm, wR2 = 0.0497, 250 F²2 values and 17 variable parameters. PrRhMg and NdRhMg crystallize with the TiNiSi type: Pnma, Z = 4, a = 721.62(7), b = 415.98(4), c = 869.47(8) pm, wR2 = 0.1864, 440 F² values, 20 variables for PrRhMg and a = 720.6(1), b = 417.6(1), c = 868.8(1) pm, wR2 = 0.0779, 425 F² values, 22 variables for NdRhMg. Refinements of the occupancy parameters revealed mixed Mg/Rh occupancy for the magnesium sites of the cerium and the neodymium compound leading to the compositions CeRh_1.262(8)Mg_0.738(8) and NdRh_1.114(9)Mg_0.886(9) for the investigated single crystals. From a geometrical point of view, the four crystal structures are built up from different rhodium centered trigonal prisms. The rhodium and magnesium atoms form three‐dimensional [RhMg] networks in which the rare earth metal atoms are located in different types of channels. The networks show Rh—Mg and Mg—Mg bonding.     

Di‐ and triphenylacetate complexes of yttrium and europium

The significant variety in the crystal structures of rare‐earth carboxylate complexes is due to both the large coordination numbers of the rare‐earth cations and the ability of the carboxylate anions to form several types of bridges between rare‐earth metal atoms. Therefore, these complexes are represented by mono‐, di‐ and polynuclear complexes, and by coordination polymers. The interaction of LnCl₃(thf)_x (Ln = Eu or Y; thf is tetrahydrofuran) with sodium or diethylammonium diphenylacetate in methanol followed by recrystallization from a DME/THF/hexane solvent mixture (DME is 1,2‐dimethoxyethane) leads to crystals of the non‐isomorphic dinuclear complexes tetrakis(μ‐2,2‐diphenylacetato)‐κ⁴O:O′;κ³O,O′:O′;κ³O:O,O′‐bis[(1,2‐dimethoxyethane‐κ²O,O′)(2,2‐diphenylacetato‐κ²O,O′)europium(III)], [Eu(C₁₄H₁₁O₂)₆(C₄H₁₀O₂)₂], (I), and tetrakis(μ‐2,2‐diphenylacetato)‐κ⁴O:O′;κ³O,O′:O′;κ³O:O,O′‐bis[(1,2‐dimethoxyethane‐κ²O,O′)(2,2‐diphenylacetato‐κ²O,O′)yttrium(III)], [Y(C₁₄H₁₁O₂)₆(C₄H₁₀O₂)₂], (II), possessing monoclinic (P2₁/c) symmetry. The [Ln(Ph₂CHCOO)₃(dme)]₂ molecule (Ln = Eu or Y) lies on an inversion centre and exhibits three different coordination modes of the diphenylacetate ligands, namely bidentate κ²O,O′‐terminal, bidentate μ₂‐κ¹O:κ¹O′‐bridging and tridentate μ₂‐κ¹O:κ²O,O′‐semibridging. The terminal and bridging ligands in (I) are disordered over two positions, with an occupancy ratio of 0.806 (2):0.194 (2). The interaction of EuCl₃(thf)₂ with Na[Ph₃CCOO] in methanol followed by crystallization from hot methanol produces crystals of tetrakis(methanol‐κO)tris(2,2,2‐triphenylacetato)‐κ⁴O:O′;κO‐europium(III) methanol disolvate, [Eu(C₁₉H₁₅O₂)₃(CH₃OH)₄]·2CH₃OH, (III)·2MeOH, with triclinic (P) symmetry. The molecule of (III) contains two O,O′‐bidentate and one O‐monodentate terminal triphenylacetate ligand. (III)·2MeOH possesses one intramolecular and four intermolecular hydrogen bonds, forming a [(III)·2MeOH]₂ dimer with two bridging methanol molecules.     

Ternary phase diagrams of DNTF and TNAZ and their eutectics

The eutectic ternary phase diagrams of some typical volatilizable energetic materials have been investigated by high pressure differential scanning calorimeter (PDSC). The ternary H–X phase diagrams for TNT/TNAZ/DNTF (TTD) and TNAZ/DNTF/RDX (TDR) systems were constructed by the correlation of the apparent fusion heat with the composition (H–X method). And, the ternary T–X phase diagrams (the temperature dependence on composition) for the two ternary systems were constructed by calculating from the data of the five T–X binary phase diagrams. The eutectic compositions (mol%) of TTD and TDR ternary systems were obtained to be 52.3/27.3/20.4 (H–X method), 53.2/25.8/21.0 (T–X method) and 54.9/39.6/5.5 (H–X method), 55.1/42.2/2.7 (T–X method), respectively. The eutectic temperatures of the ternary systems were obtained by PDSC determination and T–X method calculation to be 76.5 and 76.7 °C, 47.5 and 50.2 °C, respectively. It is shown that the results obtained by two methods are in agreement and the error in measuring or calculating eutectic compositions and temperatures for the two ternary systems are within allowable ranges of ±3 mol% and ±3 °C, respectively. Moreover, by means of constructing two ternary H–X phase diagrams with different fixed composition of a component and comparing the apparent fusion heat of eutectics with calculated one, the results obtained from H–X method for TTD system were proved. The results showed that the gasification or volatilization of easy volatile materials could be efficiently restrained by high pressure atmosphere, and the perfectly and ideally H–X ternary phase diagrams can be constructed. In comparison with T–X method, H–X method has as a virtue of being quick and simple, especially on constructing ternary phase diagram.     

Mononuclear Formamidinate Complexes of Lithium and Sodium

Treatment of N,N′‐bis(aryl)formamidines (FXylH = N,N′‐bis(2,6‐dimethylphenyl)formamidine, FEtH = N,N′‐bis(2,6‐diethylphenyl)formamidine, FisoH = N,N′‐bis(2,6‐diisopropylphenyl)formamidine) with nBuLi in the presence of tmeda (= N,N,N′,N′‐tetramethylethylenediamine) led to deprotonation of the amidine affording [Li(FXyl)(tmeda)] ( 1 ), [Li(FEt)(tmeda)] ( 2 ) and [Li(Fiso)(tmeda)] ( 3 ) respectively. Similar treatment of FXylH and FisoH with [Na{N(SiMe₃)₂}] in THF and pmdeta (= N,N,N′,N″,N″‐pentamethyldiethylenetriamine) yielded [Na(FXyl)(pmdeta)] ( 4 ) and [Na(Fiso)(pmdeta)] ( 5 ). All complexes were characterised by spectroscopy (NMR and IR) and X‐ray crystallography. Due to the bulkiness of the formamidinate ligands and the multidentate nature of the supporting neutral amine ligands (tmeda and pmdeta), all compounds were mononuclear with η²‐chelating formamidinate ligands in the solid state.     

Reaction of Phenylurea and N-Trimethylsilyl-N'-phenylurea with Vanadocene and N-Bromosuccinimide

Phenylurea and N-trimethylsilyl-N'-phenylurea react with vanadocene (Cp₂V) in toluene to give N-(⁵-cyclopentadienyl)vanadio-N'-phenylurea as a major product and Cp₂VN = C = O and aniline as byproducts. The reaction of N-trimethylsilyl-N'-phenylurea with N-bromosuccinimide in THF produces, instead of expected N-phenylureidosuccinimide and bromotrimethylsilane, succinimide and N-(p-bromophenyl)-N-trimethylsilylurea which hydrolyzes to form (p-bromophenyl)urea.     

Synthesis and Structure of N,N-Dimethyldithiocarbamates of Tetraphenylantimony and Tetra-p-tolylantimony

Tetraphenylantimony N,N-dimethyldithiocarbamate (I) and tetra-p-tolylantimony N,N-dimethyldithiocarbamate (II) were synthesized via the reaction of tetraarylantimony chloride Ar₄SbCl (Ar = C₆H₅ or C₆H₄Me-4) with sodium N,N-dimethyldithiocarbamate in water. According to the X-ray diffraction data, the tetraarylantimony N,N-dimethyldithiocarbamate molecules have a distorted octahedral configuration. The Sb–S bond lengths are equal to 2.7158(5) Å, 2.7440(5) Å and 2.761(2) Å, 2.8002(2) Å for I and II, respectively.     

Synthesis and crystal structures of halogenated oxathiazolones and an unexpected propanamide

The known 1,3,4-oxathiazol-2-ones with crystal structures reported in the Cambridge Structural Database are limited (13 to date) and this article expands the library to 15. In addition, convenient starting materials for the future exploration of 1,3,4-oxathiazol-2-ones are detailed. An unexpected halogenated propanamide has also been identified as a by-product of one reaction, presumably reacting with HCl generated in situ. The space group of 5-[(E)-2-chloroethenyl]-1,3,4-oxathiazol-2-one, C₄H₂ClNO₂S, ( 1 ), is P2₁, with a high Z′ value of 6; the space group of rac-2,3-dibromo-3-chloropropanamide, C₃H₄Br₂ClNO, ( 2 ), is P2₁, with Z′ = 4; and the structure of rac-5-(1,2-dibromo-2-phenylethyl)-1,3,4-oxathiazol-2-one, C₁₀H₇Br₂NO₂S, ( 3 ), crystallizes in the space group Pca2₁, with Z′ = 1. Both of the structures of compounds 2 and 3 are modeled with two-component disorder and each molecular site hosts both of the enantiomers of the racemic pairs (S,S)/(R,R) and (R,S)/(S,R), respectively.     

Preparation and Crystal Structures of Ruthenium and Osmium Oxide Tetrahalides

RuOF₄ as the highest valence oxide fluoride exist as a molecular compound (a = 606.0(1), b = 836.1(1), c = 626.3(1) pm, β = 91.637(3), Z = 4; P2₁/n) as well as fluorine bridged polymer (a = 547.7(2), b = 928.5(3), c = 1252.4(3) pm, Z = 8, P2₁2₁2₁). A reproducible method for pure, deep blue OsOF₄ is given. Pure OsOF₄‐I is isostructural to the fluorine bridged polymeric RuOF₄ (a = 554.6(1), b = 955.4(2), c = 1278.4(2), Z = 8, P2₁2₁2₁). OsOF₄‐II is also a fluorine bridged polymer (a = 537.8(2), b = 1274.8(4), c = 555.2(2), β = 117.716(6)°, Z = 4, P2₁/c). OsOCl₄ again is a molecular species (a = 938.9(2), b = 561.3(1), c = 1192.0(2), β = 109.944(4)°, Z = 4, P2₁/c).     

A concise and versatile route to tetrahydro‐1‐benzazepines carrying [a]‐fused heterocyclic units: synthetic sequence and spectroscopic characterization,and the molecular and supramolecular structures of one intermediate and two products

A concise, efficient and versatile route from simple starting materials to tricyclic tetrahydro‐1‐benzazepines carrying [a]‐fused heterocyclic units is reported. Thus, the easily accessible methyl 2‐[(2‐allyl‐4‐chlorophenyl)amino]acetate, (I), was converted, via (2RS,4SR)‐7‐chloro‐2,3,4,5‐tetrahydro‐1,4‐epoxy‐1‐benzo[b]azepine‐2‐carboxylate, (II), to the key intermediate methyl (2RS,4SR)‐7‐chloro‐4‐hydroxy‐2,3,4,5‐tetrahydro‐1H‐benzo[b]azepine‐2‐carboxylate, (III). Chloroacetylation of (III) provided the two regioisomers methyl (2RS,4SR)‐7‐chloro‐1‐(2‐chloroacetyl)‐4‐hydroxy‐2,3,4,5‐tetrahydro‐1H‐benzo[b]azepine‐2‐carboxylate, (IVa), and methyl (2RS,4SR)‐7‐chloro‐4‐(2‐chloroacetoxy)‐2,3,4,5‐tetrahydro‐1H‐benzo[b]azepine‐2‐carboxylate, C₁₄H₁₅Cl₂NO₄, (IVb), as the major and minor products, respectively, and further reaction of (IVa) with aminoethanol gave the tricyclic target compound (4aRS,6SR)‐9‐chloro‐6‐hydroxy‐3‐(2‐hydroxyethyl)‐2,3,4a,5,6,7‐hexahydrobenzo[f]pyrazino[1,2‐a]azepine‐1,4‐dione, C₁₅H₁₇ClN₂O₄, (V). Reaction of ester (III) with hydrazine hydrate gave the corresponding carbohydrazide (VI), which, with trimethoxymethane, gave a second tricyclic target product, (4aRS,6SR)‐9‐chloro‐6‐hydroxy‐4a,5,6,7‐tetrahydrobenzo[f][1,2,4]triazino[4,5‐a]azepin‐4(3H)‐one, C₁₂H₁₂ClN₃O₂, (VII). Full spectroscopic characterization (IR, ¹H and ¹³C NMR, and mass spectrometry) is reported for each of compounds (I)–(III), (IVa), (IVb) and (V)–(VII), along with the molecular and supramolecular structures of (IVb), (V) and (VII). In each of (IVb), (V) and (VII), the azepine ring adopts a chair conformation and the six‐membered heterocyclic rings in (V) and (VII) adopt approximate boat forms. The molecules in (IVb), (V) and (VII) are linked, in each case, into complex hydrogen‐bonded sheets, but these sheets all contain a different range of hydrogen‐bond types: N—H…O, C—H…O, C—H…N and C—H…π(arene) in (IVb), multiple C—H…O hydrogen bonds in (V), and N—H…N, O—H…O, C—H…N, C—H…O and C—H…π(arene) in (VII).     

Application of Phytochemical and Elemental Profiling,Chemometric Multivariate Analyses,and Biological Activities for Characterization and Discrimination of Fruits of Four Garcinia Species

Abstract

Species of Garcinia (Guttiferae) are used for flavoring curries, as a supplement, and to treat various diseases. This study describes the comparison and discrimination of Garcinia cambogia, Garcinia indica, Garcinia mangostana and Garcinia atroviridis fruits by analyzing their major phytochemicals, elemental content, antioxidant, antidiabetic, and anticholinesterase enzymes activities. For phytochemical and elemental profiling, ultraviolet (UV), near infrared/infrared (NIR/IR), inductively coupled plasma-optical emission spectroscopy (ICP-OES) and ICP-mass spectrometric (ICP-MS) techniques were used. The chemometric multivariate tests of linear discriminant and principal component analyses (LDA, PCA) were used to discriminate the subject fruit samples. Spectroscopic data showed resonances of phenolics and flavonoidal constituents present in the fruits. G. mangostana exhibited the highest phenolics (721.6 to 2815.3?µM GAE/g), whereas G. cambogia was rich in flavonoids (51.9 to 2709.2?µM QE/g). Anthocyanin (cyanidin-3-O-glucoside) evaluated by high performance liquid chromatographic was 9.01?mg/kg in G. mangostana fruit. In the analyzed fruits, Ca, K and Na were high, trace essential elements were at appreciable contents, whereas the toxic elements As, Cd, Tl, and Pb were within the safe limits. G. mangostana contained potent free radicals and cholinesterase enzyme inhibitors, whereas G. cambogia inhibited α-amylase enzyme more significantly. PCA and LDA discriminated the fruit samples with distinct classification and variability indices. The analyzed fruits were shown to be good sources of free radicals, cholinesterase, and α-amylase enzymes inhibition, mineral and essential elements, and safe for human consumption.