Synthesis and characterization of bromo‐, arylazo‐, and heterocyclic‐fused troponoids containing a 1,3‐benzodioxole system

A facile synthesis of a series of novel bromo‐, arylazo‐, and heterocyclic fused troponoid compounds containing 1,3‐benzodioxole system is described. The 7‐bromo‐, 5,7‐dibromo‐, and 5‐arylazo‐substituted 3‐[(2E)‐3‐(1,3‐benzodioxol‐5‐yl)prop‐2‐enoyl]tropolones ( 2 , 3 , and 5 , 6 , 7 ) were obtained by direct bromination or azo‐coupling reactions of 3‐[(2E)‐3‐(1,3‐benzodioxol‐5‐yl)prop‐ 2‐enoyl]tropolone ( 1 ) with bromine, and diazonium salts of aniline derivatives, respectively. 3‐[(2E)‐3‐(1,3‐Benzodioxol‐5‐yl)prop‐2‐enoyl]‐5‐bromotropolone ( 4 ) was obtained from 3‐acetyl‐5‐bromotropolone via one‐pot aldol dehydration reaction with piperonal. Tropolones 2, 3 , and 4 were subjected to nucleophilic cyclization with bifunctional hydroxylamine hydrochloride and phenylhydrazine hydrochloride to give the corresponding isoxazolo‐ and pyrazolo‐fused tropones ( 8 , 9 , 10 , 11 , 12 , 13 ), respectively. J. Heterocyclic Chem., (2012).     

Lignans from Phryma leptostachya L.

Three new lignans, haedoxan J ( 1 ), phrymarolin III ( 2 ), and phrymarolin IV ( 3 ), as well as eight known lignans, leptostachyol acetate, haedoxan A, 1‐(4,6‐dimethoxy‐1,3‐benzodioxol‐5‐yl)dihydro‐4‐(6‐methoxy‐1,3‐benzodioxol‐5‐yl)‐1H,3H‐furo[3,4‐c]furan‐3a(4H)‐yl acetate, 4‐(4,6‐dimethoxy‐1,3‐benzodioxol‐5‐yl)dihydro‐1‐(4‐methoxy‐1,3‐benzodioxol‐5‐yl)‐1H,3H‐furo[3,4‐c]furan‐3a(4H)‐yl acetate, 4‐[(4,6‐dimethoxy‐1,3‐benzodioxol‐5‐yl)oxy]dihydro‐1‐(6‐methoxy‐1,3‐benzodioxol‐5‐yl)‐1H,3H‐furo[3,4‐c]furan‐3a(4H)‐yl acetate, leptostachyol acetate C, 4‐(4,6‐dimethoxy‐1,3‐benzodioxol‐5‐yl)dihydro‐1‐(6‐methoxy‐1,3‐benzodioxol‐5‐yl)‐1H,3H‐furo[3,4‐c]furan‐3a(4H)‐yl acetate, and phrymarin II, were isolated from the plant Phryma leptostachya L. The structures of the new compounds were elucidated by analyzing their spectroscopic data and comparing with data reported in the literature.     

A Novel Norlignan and a Novel Phenylpropanoid from Peperomia tetraphylla

A novel cyclobutane‐type norlignan, peperotetraphin (=methyl rel‐(1R,2S,3S)‐2,3‐bis(7‐methoxy‐1,3‐benzodioxol‐5‐yl)cyclobutanecarboxylate; 1 ), and a novel phenylpropanoid, i.e., methyl (2E)‐3‐(7‐methoxy‐1,3‐benzodioxol‐5‐yl)prop‐2‐enoate ( 2 ), along with three known compounds, α‐asarone (=1,2,4‐trimethoxy‐5‐[(1E)‐prop‐1‐en‐1‐yl]benzene), vanillic acid (=4‐hydroxy‐3‐methoxybenzoic acid), and veratric acid (=3,4‐dimethoxybenzoic acid), were isolated from the EtOH extract of the whole plant of Peperomia tetraphylla. Their structures were determined by spectroscopic methods, especially 1D‐ and 2D‐NMR techniques. This is the first report of naturally occurring cyclobutane‐type norlignans.     

Cyclobutanoid Amides from Piper arborescens

Two new cyclobutanoid amides, piperarborenine A (=1,1′‐{[(1α,2α,3β,4β)‐2,4‐bis(3,4‐dimethoxyphenyl)cyclobutane‐1,3‐diyl]dicarbonyl}bis[5,6‐dihydropyridin‐2(1H)‐one]; 1 ) and piperarborenine B (=1,1′‐{[(1α,2α,3β,4β)‐2‐(3,4‐dimethoxyphenyl)‐4‐(3,4,5‐trimethoxyphenyl)cyclobutane‐1,3‐diyl]dicarbonyl}bis[5,6‐dihydropyridin‐2(1H)‐one]; 2 ) were isolated from the stem of Piper arborescens, besides two known cyclobutanoid amides, piperarboresine (=1,1′‐{[(1α,2α,3β,4β)‐2‐(7‐methoxy‐1,3‐benzodioxol‐5‐yl)‐4‐(3,4,5‐trimethoxyphenyl)cyclobutane‐1,3‐diyl]dicarbonyl}bis[5,6‐dihydropyridin‐2(1H)‐one]; 3 ) and piplartine‐dimer A (=1,1′‐{[(1α,2α,3β,4β)‐2,4‐bis(3,4,5‐trimethoxyphenyl)cyclobutane‐1,3‐diyl]dicarbonyl}bis[5,6‐dihydropyridin‐2(1H)‐one]; 4 ). The structures of the two new compounds were determined by spectral analyses.     

One‐Pot,Asymmetric and Diastereoselective Four‐Component Synthesis of Polyfunctional (Z)‐Alkenyl Methyl Sulfones with Three Stereogenic Centers

The reaction of 1‐(trimethylsilyloxy)cyclopentene ( 9 ) with (±)‐1,3,5‐triisopropyl‐2‐(1‐(RS)‐{[(1E)‐2‐methylpenta‐1,3‐dienyl]oxy}ethyl)benzene ((±)‐ 4a ) in SO₂/CH₂Cl₂ containing (CF₃SO₂)₂NH, followed by treatment with Bu₄NF and MeI gave a 3.0 : 1 mixture of (±)‐(2RS)‐2{(1RS,2Z,4SR)‐2‐methyl‐4‐(methylsulfonyl)‐1‐[(RS)‐1‐(2,4,6‐triisopropylphenyl)ethoxy]pent‐2‐en‐1‐yl}cyclopentanone ((±)‐ 10 ) and (±)‐(2RS)‐2‐{(1RS,2Z)‐2‐methyl‐4‐[(SR)‐methylsulfonyl]‐1‐[(SR)‐1‐(2,4,6‐triisopropylphenyl)ethoxy]pent‐2‐en‐1‐yl}cyclopentanone ((±)‐ 11 ). Similarly, enantiomerically pure dienyl ether (−)‐(1S)‐ 4a reacted with 1‐(trimethylsilyloxy)cyclohexene ( 12 ) to give a 14.1 : 1 mixture of (−)‐(2S)‐2‐{(1S,2Z,4R)‐2‐methyl‐4‐(methylsulfonyl)‐1‐[(S)‐1‐(2,4,6‐triisopropylphenyl)ethoxy]pent‐2‐enyl}cyclohexanone ((−)‐ 13a ) and its diastereoisomer 14a with (1S,2R,4R) or (1R,2S,4S) configuration. Structures of (±)‐ 10 , (±)‐ 11 , and (−)‐ 13a were established by single‐crystal X‐ray crystallography. Poor diastereoselectivities were observed with the (E,E)‐2‐methylpenta‐1,3‐diene‐1‐ylethers (+)‐ 4b and (−)‐ 4c bearing ( 1 S )‐1‐phenylethyl and (1S)‐1‐(pentafluorophenyl)ethyl groups instead of the Greene's auxiliary ((1S)‐(2,4,6‐triisopropylphenyl)ethyl group). The results demonstrate that high α/β‐syn and asymmetric induction (due to the chiral auxiliary) can be obtained in the four‐component syntheses of the β‐alkoxy ketones. The method generates enantiomerically pure polyfunctional methyl sulfones bearing three chiral centers on C‐atoms and one (Z)‐alkene moiety.     

Three New Neolignans from the Aril of Myristica fragrans

Three new neolignans, named 1‐deoxycarinatone ( 1 ), isodihydrocarinatidin ( 2 ), and isolicarin A ( 3 ), together with the known neolignan (+)‐dehydrodiisoeugenol ( 4 ), were isolated from mace (the aril of Myristica fragrans Houtt .). Their structures were elucidated as 2‐[(1S)‐2‐(4‐hydroxy‐3‐methoxyphenyl)‐1‐methylethyl]‐6‐methoxy‐4‐(prop‐2‐enyl)phenol ( 1 ), 4‐[(2R,3R)‐2,3‐dihydro‐7‐methoxy‐3‐methyl‐5‐(prop‐2‐enyl)benzofuran‐2‐yl]‐2‐methoxyphenol ( 2 ), and 4‐{(2S,3R)‐2,3‐dihydro‐7‐methoxy‐3‐methyl‐5‐[(1E)‐prop‐1‐enyl]benzofuran‐2‐yl}‐2‐methoxyphenol ( 3 ) on the basis of spectroscopic data.     

Two polymorphs and the diethylammonium salt of the barbiturate eldoral

Polymorph (Ia) of eldoral [5‐ethyl‐5‐(piperidin‐1‐yl)barbituric acid or 5‐ethyl‐5‐(piperidin‐1‐yl)‐1,3‐diazinane‐2,4,6‐trione], C₁₁H₁₇N₃O₃, displays a hydrogen‐bonded layer structure parallel to (100). The piperidine N atom and the barbiturate carbonyl group in the 2‐position are utilized in N—H...N and N—H...O=C hydrogen bonds, respectively. The structure of polymorph (Ib) contains pseudosymmetry elements. The two independent molecules of (Ib) are connected via N—H...O=C(4/6‐position) and N—H...N(piperidine) hydrogen bonds to give a chain structure in the [100] direction. The hydrogen‐bonded layers, parallel to (010), formed in the salt diethylammonium 5‐ethyl‐5‐(piperidin‐1‐yl)barbiturate [or diethylammonium 5‐ethyl‐2,4,6‐trioxo‐5‐(piperidin‐1‐yl)‐1,3‐diazinan‐1‐ide], C₄H₁₂N⁺·C₁₁H₁₆N₃O₃⁻, (II), closely resemble the corresponding hydrogen‐bonded structure in polymorph (Ia). Like many other 5,5‐disubstituted derivatives of barbituric acid, polymorphs (Ia) and (Ib) contain the R₂²(8) N—H...O=C hydrogen‐bond motif. However, the overall hydrogen‐bonded chain and layer structures of (Ia) and (Ib) are unique because of the involvement of the hydrogen‐bond acceptor function in the piperidine group.     

Alogliptin and its benzoate salt

The crystal structure of the free base of the antidiabetic drug alogliptin [systematic name: 2‐({6‐[(3R)‐3‐aminopiperidin‐1‐yl]‐3‐methyl‐2,4‐dioxo‐1,2,3,4‐tetrahydropyrimidin‐1‐yl}methyl)benzonitrile], C₁₈H₂₁N₅O₂, displays a two‐dimensional N—H...O hydrogen‐bonded network. It contains two independent molecules, which have the same conformation but differ in their hydrogen‐bond connectivity. In the crystal structure of the benzoate salt (systematic name: (3R)‐1‐{3‐[(2‐cyanophenyl)methyl]‐1‐methyl‐2,6‐dioxo‐1,2,3,6‐tetrahydropyrimidin‐4‐yl}piperidin‐3‐aminium benzoate), C₁₈H₂₂N₅O₂⁺·C₇H₅O₂⁻, the NH₃⁺ group of the cation is engaged in three intermolecular N—H...O hydrogen bonds to yield a hydrogen‐bonded layer structure. The benzoate salt and the free base differ fundamentally in the conformations of their alogliptin moieties.     

Intermolecular C—H...O and C—H...X interactions in substituted spiroacenaphthylene structures

In the three spiroacenaphthylene structures 5′′‐[(E)‐2,3‐dichlorobenzylidene]‐7′‐(2,3‐dichlorophenyl)‐1′′‐methyldispiro[acenaphthylene‐1,5′‐pyrrolo[1,2‐c][1,3]thiazole‐6′,3′′‐piperidine]‐2,4′′‐dione, C₃₅H₂₆Cl₄N₂O₂S, (I), 5′′‐[(E)‐4‐fluorobenzylidene]‐7′‐(4‐fluorophenyl)‐1′′‐methyldispiro[acenaphthylene‐1,5′‐pyrrolo[1,2‐c][1,3]thiazole‐6′,3′′‐piperidine]‐2,4′′‐dione, C₃₅H₂₈F₂N₂O₂S, (II), and 5′′‐[(E)‐4‐bromobenzylidene]‐7′‐(4‐bromophenyl)‐1′′‐methyldispiro[acenaphthylene‐1,5′‐pyrrolo[1,2‐c][1,3]thiazole‐6′,3′′‐piperidine]‐2,4′′‐dione, C₃₅H₂₈Br₂N₂O₂S, (III), the substituted aryl groups are 2,3‐dichloro‐, 4‐fluoro‐ and 4‐bromophenyl, respectively. The six‐membered piperidine ring in all three structures adopts a half‐chair conformation, the thiazolidine ring adopts a slightly twisted envelope and the pyrrolidine ring an envelope conformation; in each case, the C atom linking the rings is the flap atom. In all three structures, weak intramolecular C—H...O interactions are present. The crystal packing is stabilized through a number of intermolecular C—H...O and C—H...X interactions, where X = Cl in (I) and F or S in (II), and C—H...O interactions are observed predominantly in (III). In all three structures, molecules are linked through centrosymmetric ring motifs, further tailored through a relay of C—H...X [Cl in (I), Br in (II) and O in (III)] interactions.     

Phenolic Derivatives from the Root Bark of Oplopanax horridus

Four new phenolic derivatives, including two phenylpropanoid glycosides, one benzoate glycoside, and one lignan glycoside, together with one known glyceride, were isolated from the root bark of Oplopanax horridus. The structures of the new compounds were elucidated as 3‐{4‐[(6‐O‐acetyl‐β‐D ‐glucopyranosyl)oxy]‐3,5‐dimethoxyphenyl}propanoic acid ( 1 ), (+)‐[5,6,7,8‐tetrahydro‐7‐(hydroxymethyl)‐10,11‐dimehoxydibenzo[a,c][8]annulen‐6‐yl]methyl β‐D ‐glucopyranoside ( 2 ), (+)‐methyl 4‐[6‐O‐{3‐hydroxy‐3‐methyl‐5‐(1‐methylpropyl)oxy]‐5‐oxopentanoyl}‐4‐O‐(β‐D ‐glucopyranosyl)‐β‐D ‐glucopyranosyl)oxy]‐3‐methoxybenzoate ( 3 ), and 2‐methoxy‐4‐[(1E)‐3‐methoxy‐3‐oxoprop‐1‐en‐1‐yl]phenyl 6‐O‐{3‐hydroxy‐3‐methyl‐5‐[(1‐methylpropyl)oxy]‐5‐oxopentanoyl‐4‐O‐β‐d‐ glucopyranosyl‐β‐d‐ glucopyranoside ( 4 ) on the basis of spectroscopic techniques including NMR and MS analyses. The known compound was identified as glycer‐2‐yl ferulate ( 5 ) by comparing its physical and spectral data with those reported in the literature.     

Non‐iterative Asymmetric Synthesis of C15 Polyketide Spiroketals

The 2,2′‐methylenebis[furan] ( 1 ) was converted to 1‐{(4R,6S))‐6‐[(2R)‐2,4‐dihydroxybutyl]‐2,2‐dimethyl‐1,3‐dioxan‐4‐yl}‐3‐[(2R,4R)‐tetrahydro‐4,6‐dihydroxy‐2H‐pyran‐2‐yl)propan‐2‐one ((+)‐ 18 ) and its (4S)‐epimer (?)‐ 19 with high stereo‐ and enantioselectivity (Schemes 1–3). Under acidic methanolysis, (+)‐ 18 yielded a single spiroketal, (3R)‐4‐{(1R,3S,4′R,5R,6′S,7R)‐3′,4′,5′,6′‐tetrahydro‐4′‐hydroxy‐7‐methoxyspiro[2,6‐dioxabicyclo[3.3.1]nonane‐3,2′‐[2H]pyran]‐6′‐yl}butane‐1,3‐diol ((?)‐ 20 ), in which both O‐atoms at the spiro center reside in equatorial positions, this being due to the tricyclic nature of (?)‐ 20 (methyl pyranoside formation). Compound (?)‐ 19 was converted similarly into the (4′S)‐epimeric tricyclic spiroketal (?)‐ 21 that also adopts a similar (3S)‐configuration and conformation. Spiroketals (?)‐ 20 , (?)‐ 21 and analog (?)‐ 23 , i.e., (1R,3S,4′R,5R,6′R)‐3′,4′,5′,6′‐tetrahydro‐6′‐[(2S)‐2‐hydroxybut‐3‐enyl]‐7‐methoxyspiro[2,6‐dioxabicyclo[3.3.1]nonane‐3,2′‐[2H]pyran]‐4′‐ol, derived from (?)‐ 20 , were assayed for their cytotoxicity toward murine P388 lymphocytic leukemia and six human cancer cell lines. Only racemic (±)‐ 21 showed evidence of cancer‐cell‐growth inhibition (P388, ED₅₀: 6.9 μg/ml).     

Enamides via Long‐Distance Migration of Double Bonds

A new method for preparation of enamides (N‐(alken‐1‐yl) amides) by means of the ‘long‐distance' migration of the double bond in unsaturated amides in the presence of [Fe(CO)₅] is described. The method is shown to be particularly useful for the isomerization of N‐(but‐3‐enyl)amides, while, in the case of N‐(pent‐4‐enyl) and N‐(hex‐5‐enyl) amides the mixture of products was formed and the yield of the enamide was relatively low.     

New Lignan,Benzofuran, and Sesquiterpene Derivatives from the Roots of Leontopodium alpinum and L. leontopodioides

Three new compounds, including a benzofuran, 1‐{(2R*,3S*)‐3‐(β‐D ‐glucopyranosyloxy)‐2,3‐dihydro‐2‐[1‐(hydroxymethyl)vinyl]‐1‐benzofuran‐5‐yl}ethanone ( 1 ), a lignan, [(2S,3R,4R)‐4‐(3,4‐dimethoxybenzyl)‐2‐(3,4‐dimethoxyphenyl)tetrahydrofuran‐3‐yl]methyl (2E)‐2‐methylbut‐2‐enoate ( 2 ), and a silphiperfolene‐type sesquiterpene, [(1S,2Z,3aS,5aS,6R,8aR)‐1,3a,4,5,5a,6,7,8‐octahydro‐1,3a,6‐trimethylcyclopenta[c]pentalen‐2‐yl]methyl acetate ( 3 ), together with the known coumarins obliquin ( 4 ) and its 5‐methoxy derivative 5 were isolated from the roots of Leontopodium alpinum. Another known coumarin derivative, 5‐hydroxyobliquin ( 6 ), was isolated from the roots of L. leontopodioides. The structures of these compounds were established by spectroscopic studies.     

Ring‐Opening Reactions of 3‐Aryl‐1‐benzylaziridine‐2‐carboxylates and Application to the Asymmetric Synthesis of an Amphetamine‐Type Compound

Nucleophilic ring‐opening reactions of 3‐aryl‐1‐benzylaziridine‐2‐carboxylates were examined by using O‐nucleophiles and aromatic C‐nucleophiles. The stereospecificity was found to depend on substrates and conditions used. Configuration inversion at C(3) was observed with O‐nucleophiles as a major reaction path in the ring‐opening reactions of aziridines carrying an electron‐poor aromatic moiety, whereas mixtures containing preferentially the syn‐diastereoisomer were generally obtained when electron‐rich aziridines were used (Tables 1–3). In the reactions of electron‐rich aziridines with C‐nucleophiles, S_N2 reactions yielding anti‐type products were observed (Table 4). Reductive ring‐opening reaction by catalytic hydrogenation of (+)‐trans‐(2S,3R)‐3‐(1,3‐benzodioxol‐5‐yl)aziridine‐2‐carboxylate (+)‐trans‐ 3c afforded the corresponding α‐amino acid derivative, which was smoothly transformed into (+)‐tert‐butyl [(1R)‐2‐(1,3‐benzodioxol‐5‐yl)‐1‐methylethyl]carbamate((+)‐ 14 ) with high retention of optical purity (Scheme 6).     

New α‐Glucosidase Inhibitors from the Mongolian Medicinal Plant Ferula mongolica

The four new and four known sesquiterpenoid derivatives 1 – 4 and 5 – 8 , respectively, were isolated from the air‐dried roots of Ferula mongolica. The structures of these compounds were determined by spectroscopic methods and found to be rel‐(2R,3R)‐2‐[(3E)‐4,8‐dimethylnona‐3,7‐dienyl]‐3,4‐dihydro‐3,8‐dihydroxy‐2‐methyl‐2H,5H‐pyrano[2,3‐b][1]benzopyran‐5‐one ( 1 ), rel‐(2R,3R)‐2‐[(3E)‐4,8‐dimethylnona‐3,7‐dienyl]‐2,3‐dihydro‐7‐hydroxy‐2,3‐dimethyl‐4H‐furo[2,3‐b][1]benzopyran‐4‐one ( 2 ), rel‐(2R,3R)‐2‐[(3E)‐4,8‐dimethylnona‐3,7‐dienyl]‐2,3‐dihydro‐7‐hydroxy‐2,3‐dimethyl‐4H‐furo[3,2‐c][1]benzopyran‐4‐one ( 3 ), rel‐(2R,3R)‐2‐[(3E)‐4,8‐dimethylnona‐3,7‐dienyl]‐2,3‐dihydro‐7‐methoxy‐2,3‐dimethyl‐4H‐furo[3,2‐c][1]benzopyran‐4‐one ( 4 ), (4E,8E)‐1‐(2‐hydroxy‐4‐methoxyphenyl)‐5,9,13‐trimethyltetradeca‐4,8,12‐trien‐1‐one ( 5 ), the rel‐(2R,3S) diastereoisomer 6 of 2 , the rel‐(2R,3S) diastereoisomer 7 of 4 , and (4E,8E)‐1‐(2,4‐dihydroxyphenyl)‐5,9,13‐trimethyltetradeca‐4,8,12‐trien‐1‐one ( 8 ). These compounds were tested as inhibitors against the enzyme α‐glucosidase. The compounds 1 – 6 and 8 exhibited significant inhibitory activity and, therefore, represent a new class of α‐glucosidase inhibitors.     

Four Novel Dihydroisocoumarin (=3,4‐Dihydro‐1H‐2‐benzopyran‐1‐one) Glucosides from the Fungus Cephalosporium sp. AL031

Four novel dihydroisocoumarin (=3,4‐dihydro‐1H‐2‐benzopyran‐1‐one) glucosides were isolated from a culture broth of a strain of the fungus Cephalosporium sp. AL031. Their structures were elucidated as (2E,4E)‐5‐[(3S)‐5‐acetyl‐8‐(β‐D ‐glucopyranosyloxy)‐3,4‐dihydro‐6‐hydroxy‐1‐oxo‐1H‐2‐benzopyran‐3‐yl]penta‐2,4‐dienal ( 1 ), (2E,4E)‐5‐[(3S)‐5‐acetyl‐8‐(β‐D ‐glucopyranosyloxy)‐3,4‐dihydro‐6‐methoxy‐1‐oxo‐1H‐2‐benzopyran‐3‐yl]penta‐2,4‐dienal ( 2 ), (3S)‐8‐(β‐D ‐glucopyranosyloxy)‐3‐[(1E,3E,5E)‐hepta‐1,3,5‐trienyl]‐3,4‐dihydro‐6‐hydroxy‐5‐methyl‐1H‐2‐benzopyran‐1‐one ( 3 ), and (3S)‐8‐[(6‐O‐acetyl‐β‐D ‐glucopyranosyl)oxy]‐3‐[(1E,3E,5E)‐hepta‐1,3,5‐trienyl]‐3,4‐dihydro‐6‐methoxy‐5‐methyl‐1H‐2‐benzopyran‐1‐one ( 4 ) by spectroscopic methods, including 2D‐NMR techniques and chemical methods.     

Neoclerodane Diterpenes from Amoora stellato‐squamosa

From the twigs of Amoora stellato‐squamosa, five new neoclerodane diterpenes have been isolated and characterized, methyl (13E)‐2‐oxoneocleroda‐3,13‐dien‐15‐oate (=methyl (2E)‐3‐methyl‐5‐[(1S,2R,4aR,8aR)‐1,2,3,4,4a,7,8,8a‐octahydro‐1,2,4a,5‐tetramethyl‐7‐oxo‐naphthalen‐1‐yl]pent‐2‐enoate; 1 ), (13E)‐2‐oxoneocleroda‐3,13‐dien‐15‐ol (=(4aR,7R,8S,8aR)‐1,2,4a,5,6,7,8,8a‐octahydro‐8‐[(E)‐5‐hydroxy‐3‐methylpent‐3‐enyl]‐4,4a,7,8‐tetramethylnaphthalen‐2(1H)‐one; 2 ), (3α,4β,13E)‐neoclerod‐13‐ene‐3,4,15‐triol (=(1R,2R,4aR, 5S,6R,8aR)‐decahydro‐5‐[(E)‐5‐hydroxy‐3‐methylpent‐3‐enyl]‐1,5,6,8a‐tetramethylnaphthalene‐1,2‐diol; 3 ), (3α,4β,13E)‐4‐ethoxyneoclerod‐13‐ene‐3,15‐diol (=(1R,2R,4aR,5S,6R,8aR)‐1‐ethoxydecahydro‐5‐[(E)‐5‐hydroxy‐3‐methylpent‐3‐enyl]‐1,5,6,8a‐tetramethylnaphthalen‐2‐ol; 4 ), and (3α,4β,14RS)‐neoclerod‐13(16)‐ ene‐3,4,14,15‐tetrol (=(1R,2R,4aR,5S,6R,8aR)‐decahydro‐5‐[3‐(1,2‐dihydroxyethyl)but‐3‐enyl]‐1,5,6,8a‐tetramethylnaphthalene‐1,2‐diol; 5 ), together with two known compounds, (13E)‐neocleroda‐3,13‐diene‐15,18‐diol ( 6 ) and (13S)‐2‐oxoneocleroda‐3,14‐dien‐13‐ol ( 7 ).     

2,2′‐[(Disulfanediyl)bis{5‐[(1E)‐(2‐hydroxybenzylidene)amino]‐1,3‐thiazole‐4,2‐diyl}]diphenol: synthesis,crystal structure and calculation of molecular hyperpolarizability

The title Schiff base compound {systematic name: 2‐[5‐[(E )‐(2‐hydroxybenzylidene)amino]‐4‐(2‐{5‐[(E )‐(2‐hydroxybenzylidene)amino]‐2‐(2‐hydroxyphenyl)‐1,3‐thiazol‐4‐yl}disulfanyl)‐1,3‐thiazol‐2‐yl]phenol}, C₃₂H₂₂N₄O₄S₄, incorporating a disulfanediyl (dithio) linkage, was obtained from the condensation reaction between two equivalents of salicylaldehyde and one equivalent of dithiooxamide in dimethylformamide, and was characterized by elemental analysis, IR spectroscopic analysis and single‐crystal X‐ray diffraction. A one‐dimensional chain is formed along the b axis via double intermolecular C—H…S hydrogen bonds. The HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) energies and some related molecular parameters were calculated at the B3LYP/6‐311G(d,p) level of theory. The molecular hyperpolarizability was also calculated.     

Curcumaromins A,B, and C,Three Novel Curcuminoids from Curcuma aromatica

Three novel curcuminoids, curcumaromins A–C ( 1 – 3 , resp.), along with a known compound, longiferone B ( 4 ) were isolated from Curcuma aromatica Salisb . The structures of the new compounds were elucidated as (1E,4Z,6E)‐5‐hydroxy‐7‐{4‐hydroxy‐3‐[(1R*,6R*)‐3‐methyl‐6‐(propan‐2‐yl)cyclohex‐2‐en‐1‐yl)phenyl}‐1‐(4‐hydroxyphenyl)hepta‐1,4,6‐trien‐3‐one ( 1 ), 2,3‐dihydro‐2‐(4‐hydroxyphenyl)‐6‐[(E)‐2‐(4‐hydroxyphenyl)ethenyl]‐5‐[(1R*,6R*)‐3‐methyl‐6‐(propan‐2‐yl)cyclohex‐2‐en‐1‐yl]‐4H‐pyran‐4‐one ( 2 ), and (1E,6E)‐1,7‐bis(4‐hydroxyphenyl)‐4‐[(1R*,6R*)‐3‐methyl‐6‐(propan‐2‐yl)cyclohex‐2‐en‐1‐yl]hepta‐1,6‐diene‐3,5‐dione ( 3 ) on the basis of spectroscopic analysis. Curcumaromins A–C ( 1 – 3 ) represented the first examples of menthane monoterpene‐coupled curcuminoids. The known compound, longiferone B ( 4 ), was the first daucane sesquiterpene isolated from the genus Curcuma.     

A Facile Synthesis of Oxoindenothiazine and Dioxospiro(indene‐2,4′‐thiazine) Derivatives from (Substituted ethylidene)hydrazinecarbothioamides

(E)‐2‐[2‐(1‐Substituted ethylidene)hydrazinyl]‐5‐oxo‐9b‐hydroxy‐5,9b‐dihydroindeno[1,2‐d][1,3]‐thiazine‐4‐carbonitriles and (E)‐5‐oxo‐[(E)‐(1‐substituted ethylidene)hydrazinyl]‐2,5‐dihydroindeno[1,2‐d][1,3]thiazine‐4‐carbonitriles have been obtained from the reaction of 2‐(substituted ethylidene)hydrazinecarbothioamides with 2‐(1,3‐dioxo‐2,3‐dihydro‐1H‐inden‐2‐ylidene)propanedinitrile ( 1 ) in ethyl acetate solution. However, (Z)‐6′‐amino‐1,3‐dioxo‐3′‐substituted‐2′‐[(E)‐(1‐phenylethylidene)hydrazono]‐1,2′,3,3′‐tetrahydrospiro(indene‐2,4′‐[1,3]thiazine)‐5′‐carbonitriles were observed during the reaction of N‐substituted‐2‐(1‐phenylethylidene)hydrazinecarbothioamides with ( 1 ). The structure assignment of products has been confirmed on the basis of ¹H‐, ¹³C‐NMR, and mass spectrometry, as well as theoretical calculations.