Fragmentation pathways of deprotonated amide‐sulfonamide CXCR4 inhibitors investigated by ESI‐IT‐MSn,ESI‐Q‐TOF‐MS/MS and DFT calculations

Amide‐sulfonamides provide a potent anti‐inflammatory scaffold targeting the CXCR4 receptor. A series of novel amide‐sulfonamide derivatives were investigated for their gas‐phase fragmentation behaviors using electrospray ionization ion trap mass spectrometry and quadrupole time‐of‐flight mass spectrometry in negative ion mode. Upon collision‐induced dissociation (CID), deprotonated amide‐sulfonamides mainly underwent either an elimination of the amine to form the sulfonyl anion and amide anion or a benzoylamide derivative to provide sulfonamide anion bearing respective substituent groups. Based on the characteristic fragment ions and the deuterium–hydrogen exchange experiments, three possible fragmentation mechanisms corresponding to ion‐neutral complexes including [sulfonyl anion/amine] complex ( INC‐1 ), [sulfonamide anion/benzoylamide derivative] complex ( INC‐2 ) and [amide anion/sulfonamide] complex ( INC‐3 ), respectively, were proposed. These three ion‐neutral complexes might be produced by the cleavages of S–N and C–N bond from the amide‐sulfonamides, which generated the sulfonyl anion (Route 1), sulfonamide anion (Route 2) and the amide anion (Route 3). DFT calculations suggested that Route 1, which generated the sulfonyl anion (ion c ) is more favorable. In addition, the elimination of SO₂ through a three‐membered‐ring transition state followed by the formation of C–N was observed for all the amide‐sulfonamides.     

Synthesis of 3-arylamino-4(3H)quinazolinone derivatives from 1-acetyl- or 1-ethoxycarbonylmethylene-2-arylhydrazines

By reacting 1-acetyl- or 1-ethoxycarbonylehloromethylene-2-arylhydrazines ( 2a-c ) with anthranilic acids (1a-b) the corresponding C-acetyl- or C-ethoxyearbonylcarbohydrazonamide derivatives (3a-d) were obtained. Ring closure of the carbohydrazonamides with acetic anhydride afforded 2-carboethoxy- or 2-acetyl-3-arylamino-4(3H)quinazolinones ( 4a-d ). The ester derivatives undergo basic hydrolysis with decarboxylation to 3-arylamino-4(3H)quinazolinones ( 5a-b ).     

Synthesis and nitration of calix[4] (aza)crowns

Calix[4] (aza) crowns containing amide groups 3a-d were synthesized by the reactions of calix[4]arene (1a) or p-tert-butylcalix[4]arene (1b) with N, N'-ethylenebis(2-chloroac-etamide) (2a) or N, N'-1,2-phenylenebis(2-chloroacetamide) (2b) by one step procedure in yields of 85-90% . Calix[4]-(aza) crowns 4a-b could be obtained by the reduction of 3a-b with LiAlH4 in yields of 51 and 67% , respectively. The nitration of 3a or 3c afforded new chromogenic calix[4]arenes 5a bearing two nitrophenol moieties and 5c bearing one nitro-phenol and one quinone moiety, respectively. The ipso-nitrations of 3b and 3d were also studied. Both gave the products containing one nitrophenol and one quinone moiety. Moreover, a very interesting calix[4]arene derivative 5d containing one cyclohexadienone moiety was also separated as the main product when 3d was ipso -nitrated.     

Antioxidant activity of aryltetralone lignans and derivatives from Virola sebifera (Aubl.)

Aryltetralone lignans bearing methylenedioxy groups (1a-b; 2a-b) were isolated from seeds of Virola sebifera. Their antioxidant activities were evaluated by inhibition of lipid peroxidation as indicated by TBARS and chemiluminescence emission (CL) assays. The lignan 1c, 'having a 2'-hydroxy-4',5'-methylenedioxyphenyl group, was the most active compound with TBARS/CL Q 1/2 values of 0.89 and 0.10 microg/mL, respectively. The catechol derivatives 3 and 4, obtained by demethylenation of lignans 1a and 2a, were of similar activity to 1c, and all were much more effective as antioxidants than alpha-tocopherol.     

Photochemical reactions of β-aminovinyl aryl thioketones

Irradiation of β-aminovinyl aryl thioketones ( 1a-b ) afforded β-aminovinyl aryl ketones ( 2a-b ). 2H-Thiopyran derivatives ( 4a-b ) were obtained when β-aminovinyl phenyl thioketone ( 1a ) was irradiated with methyl acrylate and acrylonitrile. 4H-Thiopyran derivatives ( 6,8 ) were also obtained thermally in the reaction of β-aminovinyl phenyl thioketone ( 1a ) and methyl propiolate and maleic anhydride.     

Synthesis of heierocyclic compounds from 2-phenyl-1, 2,3-triazole-4-formylhydrazine

2-Phenyl-1, 2, 3-triazole-4-formylhydrazine (2) was prepared by hydrazinolysis of the corresponding ester 1. Reaction of 2 with CS2/KOH gave the oxadiazole derivatives (3) which via, Mannich reaction with different dialkyl amines furnished 3-N, N-dialkyl derivatives (4a-c). Also, condensation of 2 with appropriate aromatic acid in POCl3 yielded oxadiazole derivatives (5a-c), or with aldehydes and ketones afforded hydrazones (6a-c). Cyclization of (6a-c) with acetic anhydride gave the desired dihydroxadiazole derivatives (7a-c). On the other hand, reaction of dithiocarbazate (8) with hydrazine hydrate gave the corresponding triazole derivative (9) which on treatment with carboxylic acids in refluxing POCl3 yielded s-triazole[3,4-b]-1, 3, 4-thiadiazole derivatives (10a-b). The structures of all the above compounds were confirmed by means of IR, 1H NMR, MS and elemental analysis.     

Synthesis of 3-(2-Phenylquinolin-4-yl)/3-(l-p-Chlorophenyl-5-methyl-1, 2,3-triazol-4-yl)-s-triazolo[3,4-b]-1, 3,4-thiadiazine Derivatives

s-Triazolo[3, 4-b]-1,3,4-thiadiazine derivatives constitute an important class of organic compounds with diverse biological activities. 2-Phenylquinoline and 1,2, 3-triazole derivatives are very attractive heterocyclic systems due to their wide use in medicine, agriculture and industry^[1]. Incorporation of 2-phenylquinoline and 1,2,3-triazole moiety into the 3-position of s-triazolo[3,4-b]-l, 3,4-thiadiazine ring system may enhance their biological activity. In light of the above findings, we synthesized some new s-triazolo[3, 4-b]-1, 3, 4-thiadiazine derivatives 2a-b~6a-b by the condensation of 4-amino-5-mercapto-3-(2-phenylquinolin-4-yl)/3-(1-p-chlorophenyl-5-methyl-1, 2,3-triazol-4-yl)-1, 2, 4-triazoles 1a-b with chloroacetalde-hyde, ω-bromo-ω-(1H-1, 2, 4-triazol-1-yl)acetophenone, chloranil, 2-bromocyclohexanone, 2, 4'-dibromoacetophenone, respectively.     

Syntheses of IAA- and IPA-amino acid conjugates

Amino acid derivatives of IAA and IPA are prepared conveniently and efficiently by coupling of readily available 2a-b with diverse free amino acids 3a-g and (3c+3c') to give compounds 4a-j, (4c+4c') and (4h+4h') in 38-70% yields. Similarly, 2a-b afforded IAA and IPA peptide conjugates 6a-b in 32-40% yields. Complete retention of chirality was supported by NMR and HPLC analysis.     

N,S-Substituted Dienes from Mono(arylthio)substituted- and S-, S,S-Substituted Dienes

Mono(thio)substituted dienes 1a-1b gave compounds 3a-c and 5d-g with piperazine and piperidine derivatives in dichloromethane. Compounds 8 , 9 , and 10 were obtained from the reactions of perchlorobutadiene ( 6 ) with 1,4-butanedithiol ( 7 ) in ethanol in the presence of sodium hydroxide. Compounds 12a-b , 13a-b were obtained from the reactions of perchlorobutadiene ( 6 ) with allylmercaptan (CH 2 =CH--CH 2 --SH) and mercaptoethanol (HO--CH 2 --CH 2 --SH).     

Synthesis of 1-aryl-5-methyl-4-substituted-l,2,3-triazoles

As 1-aryl-5-methyl-4-substituted-1,2,3-triazoles often exhibit broad spectrum biological actions, we have synthesized many heterocyclic and condensed heterocyclic compounds which contained 1-aryl-5-methyl-1,2,3-triazol-4-yl functional groups and screened their antibacterical activities^[1,2]. Our further work testified that it was necessary to go on studying such kind of compounds. In order to improve the soluble of these compounds, we chose aniline and p-toluidime as starting materials to synthesize 1-aryl-5-methyl-4-substituted-1,2,3-triazoles 1a-b, 2a-b, 3a-b, 4a-b, 5a, These new compounds all have active reaction groups such as SH, NH₂ as well as OH. So they might react with ω-substituted-ω-bromo-acetophenone and 6a-b, 7a-b, 8a-b, 9a were obtained. They are all soluble in hot alcohol. Under similar conditions it is difficult to let 4a-b react completely with ω-substituted-ω-bromo-acetophenone. We only observed a little new compounds by TLC. By Mannich reaction, 1a-b also could react with formaldelyde and p-toluidime and l0a-b were isolated. The evaluation of the biological activity is in progress.     

Electrosynthesis of hydroquinonethioethers using electrochemical oxidation of hydroquinone in the presence of thiouracil derivatives

Electrochemical oxidation of hydroquinone(1a) has been studied in the presence of 6-methyl-2-thiouracil(3a) and 6-propyl-2-thiouracil(3b) as nucleophiles in a DMF/buffer mixture,using cyclic voltammetry and controlled-potential coulometry.The results indicated that the p-quinone(2a) derived from 1a participates in a 1 4-Michael addition reaction with the thiouracil derivatives(3a–b) to form the corresponding hydroquinonethioether derivatives(6a–6b).The electrosynthesis of these compounds(6a–b) has been successfully performed on carbon rod electrodes in an undivided cell in good yield and purity.     

Benzofuran systems. Synthesis and biological examination of 1-(3-benzofuranyl)-2-phenylethanones

Novel 1-(3-benzofuranyl)-2-phcnylethanones 4a-d have been prepared by acetylation of 2-alkylbenzo-furans 2a-c with phenylacetyl chlorides 3a-b . The methoxy derivatives 4b-d have been demethylated to the corresponding phenols 5b-d with pyridinium hydrochloride. An attempt to obtain the derivatives of 4d and 5a iodinated in the phenyl ring has been undertaken. The novel compounds have been characterized by ir and nmr spectra and their biological activity examined.     

Microwave assisted synthesis of novel functionalized hydantoin derivatives and their conversion to 5-(Z) arylidene-4H-imidazoles

2-(Alkyl-1-yl)-1H-imidazol-5(4H)-ones 5a-n were synthesized via nucleophilic substitution of the methylsulfanyl group of the corresponding 2-(methylthio)-1H-imidazol-5(4H)-ones 3a-c with suitably substituted secondary amines. The starting 2-thioxo- imidazolidin-4-ones 2a,2b were prepared by condensation of thiohydantoin and benzo[b]-thiophene-3-carbaldehyde or benzofuran-3-carbaldehyde under microwave irracdiation (MW) conditions. 2-Methylthio derivatives 3a-c were prepared by treatment of 2a-b with methyl iodide in the presence of aqueous sodium hydroxide.     

Exploring the scope of poly(ethylene glycol) (PEG) as a soluble polymer matrix for the Stille cross-coupling reaction

The optimization and efficient parallel synthesis and purification of a library of biaryl, heterobiaryl, and styryl derivatives, via the first reported poly(ethylene glycol)-supported palladium-catalyzed Stille procedure, are described. Preliminary investigations into the reaction between monomethoxy poly(ethylene glycol)5000-supported iodide 1a with tributylphenyltin 2 revealed that the optimal "liquid-phase" conditions employ PdCl2(PPh3)2 (0.1 equiv) catalysis with LiCl (10 equiv) in DMF at 80 degrees C for either 48 h (at 20 mM concentration of 1a) or 24 h (at 10 mM concentration of 1a). The soluble polymer-supported reaction is superior to its solution-phase counterpart because the tributyltin side products and excess reagents are easily separated from the product intermediate 3a by precipitation of 3a into diethyl ether followed by recovery of the polymer by filtration in > 99%. In addition, the homocoupled byproduct 6 is also removed during this precipitation step. Under these conditions the transesterified biaryl adduct 4a can be isolated in 97-98% yield. The scope of this reaction was probed in a parallel format with the PEG-supported electrophiles 1a-b and a range of tributyl stannanes 2 and 7-13 under the optimized conditions vide supra. Subsequent cleavage of the polymer-supported adducts, by transesterification, and short column chromatography yielded a library of substituted methyl benzoates 4a-b and 14a-b to 20a-b in high yield (69-99%) and purity (> 95%).     

Enantioselective synthesis of (2-pyridyl)alanines via catalytic hydrogenation and application to the synthesis of L-azatyrosine

[reaction: see text] A novel method for the synthesis of (2-pyridyl)alanines 2a-b was developed by converting (2-pyridyl)dehydroamino acid derivatives 1a-b to the corresponding N-oxides 3a-b followed by asymmetric hydrogenation using (R,R)-[Rh(Et-DUPHOS)(COD)]BF(4) [(R,R)-6] catalyst and subsequent N-oxide reduction in 80-83% ee. This methodology was applied to the total synthesis of L-azatyrosine [(+)-12], an antitumor antibiotic, starting from (5-benzyloxy)-2-pyridylmethanol (7), in >96% enantiomeric purity.     

1,2,3-Triazolodiazepines. I. Preparation and benzodiazepine receptor binding of 1-benzyl- and 1-phenethyl-1,2,3-triazolo-[4,5-b][1,4]diazepines

Several new 1,2,3-triazolo[4,5-b][1,4]diazepines were prepared starting from 1-benzyl-1 and 1-phenethyl-4,5-diamino-1,2,3-triazole 2 (Scheme 1), by condensation reactions with β-diketones (Scheme 2), β-ketoesters (Scheme 3), and diethyl malonates (Scheme 4). In the first case we obtained compounds 3 and 4 with basic properties, while the ester function condensations gave cyclic amide derivatives 7, 8, 10, 12 and 13 with acid properties. Some N-methyl derivatives 11, 14 and 15 were obtained from the cyclic amide compounds. Most of compounds were tested for their ability to displace [³H]flunitrazepam from bovine brain membranes but no compound showed benzodiazepine receptor binding affinity.     

Hydrogen-bond-assisted control of H versus J aggregation mode of porphyrins stacks in an organogel system

To obtain insights into a correlation relationship between the structure and the aggregation mode in an organogel system, we synthesized gelators 2a-4a bearing a porphyrin moiety as a one-dimensional aggregation unit and amide groups as peripheral hydrogen-bonding sites. Gelators 3a and 3b bearing the amide groups at the 4-position of the meso-phenyl groups are classified as versatile gelators, gelating 10 and 14 solvents, respectively, among 23 solvents tested herein. In contrast, gelators 2a and 4a bearing the amide groups at the 3,5-positions and 3-position, respectively, are classified as poor gelators. Examination by spectroscopic methods (UV-vis, ATR-FTIR, XRD, etc.) revealed that in the organogel phase porphyrins in 3a adopt the H aggregation mode whereas those in 2a and 4a adopt the J aggregation mode. X-ray analysis of the single crystals established that in fact 3b features a columnar stack of porphyrin moieties that can be classified as the H-aggregate, whereas 2a results in a two-dimensional a-b plane, in which porphyrin moieties are arranged in the J-aggregate. Very interestingly, the difference in the H versus J aggregation mode is well-reflected by the difference in the macroscopic aggregate morphology observed by SEM: 3a + cyclohexane gel results in a one-dimensionally aggregated fibrillar structure, whereas 2a + cyclohexane gel results in a two-dimensional sheetlike structure. These findings indicate that the H versus J aggregation mode of porphyrin stacks can be controlled by the peripheral hydrogen-bonding interactions and the microscopic hydrogen-bonding network structure is well-reflected by the macroscopic SEM-observed structure.     

Rapid cleavage of unactivated, unstrained amide bonds at neutral pH

Building upon the discovery of Suggs and Pires that N-(2-hydroxyethyl)glycine amides undergo rapid amide cleavage under mild conditions [ Suggs, J. W. ; Pires, R. M. Tetrahedron Lett. 1997, 38, 2227-2230 ], we synthesized the derivatives (4aalpha,8beta,8aalpha)-1-ethylamido-8-hydroxydecahydroquinoline ( 4) and (4aalpha,8alpha,8abeta)-1-ethylamido-8-hydroxydecahydroquinoline ( 5). These two species are conformationally constrained, but steric compression is not introduced between the hydroxyl group and the amide functionality it attacks. At 20 degrees C and slightly basic pH, derivatives 4 and 5 undergo amide cleavage with half-lives of 21 min and 14 h, respectively, which correspond to rate increases of 251- and 6.3-fold relative to the acyclic analogue N-(2-hydroxyethyl)glycine amide ( 3).     

Alkylations of Resorcarenes and Calix[4]pyrroles in Phase Transfer Catalytic Systems

Calixlnlarenesarecyclicoligomersmadeupofphenolsandformaldehyde.Thisversatileclassofcompoundshasbeenextensivelystudiedinthelastdecademainlyinordertoobtainnewcomplexingagentsbyappropriatefuntionalizationoftheparentmoleculel.ResorcarenesZandcall-c[4]pyrroles'aretwosubgroupmembersofthefamilyofcalixarensandalsoattractedincreasinginterests.Aspartofaprogrammeaimedatthesynthesisofneweasy-to-makecalixarenemolecules,wedecidedtoinvestigatethealkylationofsomecalixarensinPhaseTransferCatalysis(PTC)condi…     

Synthetic utility of sydnones to couple pharmacologically important heterocycles for antitubercular activity

In the present investigation we have utilized the 3-arylsydnones 1a–c to couple two biodynamic moieties in amide derivatives 7–10. The 3-arylsydnones were brominated to 4-bromo-3-arylsydnones 2a–c which further were reacted with benzotriazole/benzothiazolin-2-thione/morpholine/diphenylamine to the corresponding final compounds. The structures of the amide derivatives were confirmed by the spectral (IR, ¹H NMR and Mass) and analytical data. Further, these were subjected to the antitubercular activity against Mycobacterium tuberculae (H37Rv). The morpholine 7a–c and benzotriazole 8a–c derivatives have exhibited good inhibition.