Syntheses of 2,4‐diaryl‐2,3‐dihydro‐1,5‐benzothiazepines

The condensation of α,β‐unsaturated ketones with substituted o‐aminothiophenols, obtained by reductive cleavage of the corresponding disulfides in the presence of triphenylphosphine, is an effective method for the synthesis of 2,4‐diaryl‐2,3‐dihydro‐1,5‐benzothiazepines under neutral conditions.     

Stereospecific synthesis of 2‐phthalimido‐2a,3,4,5‐tetrahydro‐1H‐azeto[2,1‐d][1,5]benzothiazepin‐1‐ones

2a,4‐Disubstituted 2‐phthalimido‐2a,3,4,5‐tetrahydro‐1H‐azeto[2,1‐d][1,5]benzothiazepin‐1‐ones were synthesized by cycloaddition reactions of 2,4‐disubstituted 2,3‐dihydro‐1,5‐benzothiazepines and phthalimidoketene, generated from phthalimidoacetyl chloride, in the presence of triethylamine in anhydrous benzene. The stereochemistry was discussed for the cycloaddition reaction. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:276–279, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/hc.10029     

4‐Aryl‐2‐ferrocenyl‐ and 2‐Aryl‐4‐ferrocenyl‐2,3‐dihydro‐1,5‐benzothiazepines with Potentially Biological Activities: Synthesis,Characterization, X‐ray Diffraction Studies

A series of novel 4‐aryl‐2‐ferrocenyl‐ and 2‐aryl‐4‐ferrocenyl‐2,3‐dihydro‐1,5‐benzothiazepines 3a , 3b , 3c , 3d , 3e , 3f and 6a , 6b , 6c , 6d , 6e was obtained by the condensation of 1‐aryl‐3‐ferrocenyl‐ and 3‐aryl‐1‐ferrocenyl‐2‐propenones 1a , 1b , 1c , 1d , 1e , 1f and 4a , 4b , 4c , 4d , 4e , respectively, with o‐aminothiophenol in the presence of AcOH and HCl (~64–91%). Their structures were established based on the spectroscopic data and X‐ray diffraction analysis of the compounds 3d , 5a , and 6c .     

4‐(2‐Hydroxyphenyl)‐2‐phenyl‐2,3‐dihydro‐1H‐1,5‐benzodiazepine and the 2‐(2,3‐dimethoxyphenyl)‐, 2‐(3,4‐dimethoxyphenyl)‐ and 2‐(2,5‐dimethoxyphenyl)‐substituted derivatives

The 1,5‐benzodiazepine ring system exhibits a puckered boat‐like conformation for all four title compounds [4‐(2‐hydroxyphenyl)‐2‐phenyl‐2,3‐dihydro‐1H‐1,5‐benzodiazepine, C₂₁H₁₈N₂O, (I), 2‐(2,3‐dimethoxyphenyl)‐4‐(2‐hydroxyphenyl)‐2,3‐dihydro‐1H‐1,5‐benzodiazepine, C₂₃H₂₂N₂O₃, (II), 2‐(3,4‐dimethoxyphenyl)‐4‐(2‐hydroxyphenyl)‐2,3‐dihydro‐1H‐1,5‐benzodiazepine, C₂₃H₂₂N₂O₃, (III), and 2‐(2,5‐dimethoxyphenyl)‐4‐(2‐hydroxyphenyl)‐2,3‐dihydro‐1H‐1,5‐benzodiazepine, C₂₃H₂₂N₂O₃, (IV)]. The stereochemical correlation of the two C₆ aromatic groups with respect to the benzodiazepine ring system is pseudo‐equatorial–equatorial for compounds (I) (the phenyl group), (II) (the 2,3‐dimethoxyphenyl group) and (III) (the 3,4‐dimethoxyphenyl group), while for (IV) (the 2,5‐dimethoxyphenyl group) the system is pseudo‐axial–equatorial. An intramolecular hydrogen bond between the hydroxyl OH group and a benzodiazepine N atom is present for all four compounds and defines a six‐membered ring, whose geometry is constant across the series. Although the molecular structures are similar, the supramolecular packing is different; compounds (I) and (IV) form chains, while (II) forms dimeric units and (III) displays a layered structure. The packing seems to depend on at least two factors: (i) the nature of the atoms defining the hydrogen bond and (ii) the number of intermolecular interactions of the types O—H...O, N—H...O, N—H...π(arene) or C—H...π(arene).     

Stereospecific synthesis of azeto[2,1‐d]‐ [1,5]benzothiazepin/diazepin‐1‐ones

2a,4‐Disubstituted 2‐phenoxy‐2,2a,3,4‐tetrahydro‐1H‐azeto[2,1‐d][1,5]benzothiazepin‐1‐ones and 5‐benzoyl‐2‐phenoxy‐2a,3,4,5‐tetrahydro‐azeto[1, 2‐a][1,5]benzodiazepin‐1(2H)‐ones were synthesized in moderate to good yields by stereospecific Staudinger cycloaddition reactions of 2,4‐disubstituted 2,3‐dihydro‐1,5‐benzothiazepines and 1‐benzoyl‐2,3‐dihydro‐1H‐1,5‐benzodiazepines, respectively, with phenoxy acetyl chloride in the presence of triethylamine in anhydrous benzene. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:564–569, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10196     

Synthesis of Indane‐Based 1,5‐Benzothiazepines Derived from 3‐Phenyl‐2,3‐dihydro‐1H‐inden‐1‐one and Antimicrobial Studies Thereof

In the present study, a series of 20 indane‐based 1,5‐benzothiazepines ( 5a – t ) has been prepared derived from 3‐phenyl‐2,3‐dihydro‐1H ‐inden‐1‐one ( 1 ). All the synthesized 1,5‐benzothiazepines ( 5a – t ) were screened for their in vitro antimicrobial activities against four bacteria [Bacillus subtilis (MTCC 441), Staphylococcus epidermidis (MTCC 6880), Escherichia coli (MTCC 1652), and Pseudomonas aeruginosa (MTCC 424)] and two fungi [Candida albicans (MTCC 227) and Aspergillus niger (MTCC 8189)]. Among all the tested derivatives, 5n and 5o against E. coli displayed more inhibitory activity than that of the reference drug, ciprofloxacin, while the derivatives 5c , 5m – o , 5s , and 5t against C. albicans , and 5d , 5e , 5n , 5o , 5s , and 5t against A. niger were found to be more potent than the standard drug, that is, fluconazole.     

Syntheses of some new 1,5‐benzothiazepine derivatives and their ribofuranosides as antimicrobial agents

(±)‐cis‐2‐(4‐Methoxyphenyl)‐3‐hydroxy/methoxy‐6‐ethoxy/phenoxy‐2,3‐dihydro‐1,5‐benzothiazepin‐4‐[5H/5‐chloroacetyl/5‐(4′‐methylpiperazino‐1′)acetyl]‐ones have been synthesized by the condensation of 2‐amino‐3‐ethoxy/phenoxybenzenethiol with methyl‐(±)‐trans‐3‐(4‐methoxyphenyl)glycidate in xylene. Ribofuranosides, viz. (±)‐cis‐2‐(4‐methoxyphenyl)‐3‐methoxy‐6‐ethoxy/phenoxy‐2,3‐dihydro‐1,5‐benzothiazepin‐4‐[5‐(2′,3′,5′‐tri‐O‐benzoyl‐β‐D ‐ribofuranosyl)]‐ones, have been synthesized by the treatment of 3‐methoxy derivatives of 1,5‐benzothiazepines with a derivative, sugar, viz. β‐D ‐ribofuranose‐1‐acetate‐2,3,5‐tribenzoate, in toluene in vacuo. The structures of all the synthesized ribofuranosides and their precursors have been characterized on the basis of elemental analyses and IR, ¹H NMR, and ¹³C NMR spectral data. These compounds were screened for their antimicrobial activity. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:620–625, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10051     

Synthesis of Glycaro‐1,5‐lactams and Tetrahydrotetrazolopyridine‐5‐carboxylates: Inhibitors of β‐D‐Glucuronidase and α‐L‐Iduronidase

The known glucaro‐1,5‐lactam 8 , its diastereoisomers 9 – 11 , and the tetrahydrotetrazolopyridine‐5‐carboxylates 12 – 14 were synthesised as potential inhibitors of β‐D ‐glucuronidases and α‐L ‐iduronidases. The known 2,3‐di‐O‐benzyl‐4,6‐O‐benzylidene‐D ‐galactose ( 16 ) was transformed into the D ‐galactaro‐ and L ‐altraro‐1,5‐lactams 9 and 11 via the galactono‐1,5‐lactam 21 in twelve steps and in an overall yield of 13 and 2%, respectively. A divergent strategy, starting from the known tartaric anhydride 41 , led to the D ‐glucaro‐1,5‐lactam 8 , D ‐galactaro‐1,5‐lactam 9 , L ‐idaro‐1,5‐lactam 10 , and L ‐altraro‐1,5‐lactam 11 in ten steps and in an overall yield of 4–20%. The anhydride 41 was transformed into the L ‐threuronate 46 . Olefination of 46 to the (E)‐ or (Z)‐alkene 47 or 48 followed by reagent‐ or substrate‐controlled dihydroxylation, lactonisation, azidation, reduction, and deprotection led to the lactams 8 – 11 . The tetrazoles 12 – 14 were prepared in an overall yield of 61–81% from the lactams 54, 28 , and 67 , respectively, by treatment with Tf₂O and NaN₃, followed by saponification, esterification, and hydrogenolysis. The lactams 8 – 11 and 40 and the tetrazoles 12 – 14 are medium‐to‐strong inhibitors of β‐D ‐glucuronidase from bovine liver. Only the L ‐ido‐configured lactam 10 (K_i = 94 μM ) and the tetrazole 14 (K_i = 1.3 mM ) inhibit human α‐L ‐iduronidase.     

Reactions of 2,3‐dihydro‐1H‐1,5‐benzodiazepines and chloroacetyl chlorides: Synthesis of 2a,3,4,5‐tetrahydro‐azeto [1,2‐a][1,5] benzodiazepin‐1(2H)‐ones

2a,4‐Disubstituted 5‐benzoyl‐2‐chloro/2,2‐dichloro‐2a,3,4,5‐tetrahydro‐azeto [1,2‐a] [1,5]benzodiazepin‐1 (2H)‐ones ( 3a–h ) were synthesized by cycloaddition reactions of 2,4‐disubstituted 1‐benzoyl‐2,3‐dihydr o‐1H‐1,5‐benzodiazepines ( 2a–h ) and ketenes, generated from chloroacetyl chloride or dichloroacetyl chloride in the presence of triethylamine, in anhydrous benzene. In some cases, ring contraction of benzodiazepines has also been observed. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:636–640, 2001     

Derivatives of 4‐(2‐hydro­xy­lphenyl)‐2‐phenyl‐2,3‐di­hydro‐1,5‐benzothiazepine

In the structures of 2‐(4‐chloro­phenyl)‐4‐(2‐hydroxyphenyl)‐2,3‐di­hydro‐1,5‐benzo­thia­zepine, C₂₁H₁₆ClNOS, 4‐(2‐hy­droxy­phenyl)‐2‐(4‐tolyl)‐2,3‐di­hydro‐1,5‐ben­zo­thia­zepine, C₂₂H₁₉NOS, and 4‐(2‐hydroxyphenyl)‐2‐(3‐methoxy­phenyl)‐2,3‐di­hydro‐1,5‐benzo­thia­zepine, C₂₂H₁₉NO₂S, the central seven‐membered heterocyclic rings adopt twist‐boat conformations in which the N atoms are involved in strong intramolecular hydrogen bonds with the hydroxyl H atoms, resulting in six‐membered rings.     

Bis(enaminones) as Versatile Precursors for Novel Bis([1,2,4]triazolo[1,5‐a]pyrimidines) and Bis(2‐thioxo‐2,3‐dihydropyrido[2,3‐d]pyrimidin‐4(1H)‐ones)

Novel bis([1,2,4]triazolo[1,5‐a]pyrimidines) and bis(2‐thioxo‐2,3‐dihydropyrido[2,3‐d]pyrimidin‐4(1H)‐ones) were prepared utilizing bis(enaminones) as precursors. The structures of the prepared compounds were elucidated by several spectral tools as well as elemental analyses.     

Cascade Triple‐Aldehyde Addition of 1,2,3,4‐Tetrakis(pinacolatoboryl)but‐ 2‐ene: Stereoselective Synthesis of 2,3‐Bis(alkylidene)alkane‐1,5‐diols

Treatment of (Z)‐1,2,3,4‐tetrakis(pinacolatoboryl)but‐2‐ene, prepared from 2,3‐bis(pinacolatoboryl)buta‐1,3‐diene and bis(pinacolato)diboron, with three molar equivalents of aldehyde in toluene at 100 °C gave the 2,3‐bis(alkylidene)alkane‐1,5‐anti‐diol as a single stereoisomer. The reaction is applicable to both aromatic and α‐unbranched aliphatic aldehydes. The 1,5‐anti‐diols were also synthesized by the one‐pot preparation/triple‐aldehyde addition of the tetraborylated butene. Experimental results for the stepwise treatment of the butene with two types of aldehydes suggest that the rate‐determining step of the triple‐aldehyde addition is the third allylation.     

Studies on the chemical transformations of rotenoids. 6 Synthesis and antitumor‐promoting activity of benzofuro[2,3‐d]pyridazines fused with 1,2,4‐triazole, 1,2,4‐triazine and 1,2,4‐triazepine

[1]Benzofuro[2,3‐d]pyridazines fused with 1,2,4‐triazole ( 6 and 7 ), 1,2,4‐triazine ( 8–10 ) and 1,2,4‐tri‐azepine (12) were prepared by the ring closure of 4‐hydrazino‐[1]benzofuro[2,3‐d]pyridazine ( 5 ), derived from naturally occurring rotenone. Compounds ( la and lb ) exhibited significant inhibitory activity against 12‐O‐tetradecanoylphorbol 13‐acetate (TPA)‐induced Epstein‐Barr virus early antigen (EBA‐EA) activation in Raji cells. In contrast, the fused [1]benzofuro[2,3‐d]pyridazines except 6c and 8 were quite inactive.     

Preparation of 2,3‐dihydro‐1H,5H‐pyrido[3,2,1‐ij]quinoline‐1,5‐dione derivatives

The 2,3‐dihydro‐7‐methyl‐1H,5H‐pyrido[3,2,1‐ij]quinoline‐1,5‐dione derivatives 9 and 10 were prepared from 3‐(5,7‐dimethoxy‐4‐methyl‐2‐oxo‐2H‐quinolin‐1‐yl)propionitrile ( 6 ). Cyclodehydration of the amide 8 gave 1,2‐dihydro‐7,9‐dimethoxy‐6‐methylpyimido[1,2‐a]quinolin‐3‐one ( 11 ).     

Synthesis and biological screening of 4‐(3,3‐dimethylspiro{bicyclo[2.2.1]heptan‐2,5′‐isoxazoline‐2}‐ 3′‐yl)‐2‐aryl‐2,3‐dihydro‐1H‐1,5‐benzodiazepines

A series of novel 4‐(3,3‐dimethylspiro{bicyclo[2.2.1]heptan‐2,5′‐isoxazoline‐2}‐3′‐yl)‐2‐phenyl‐2,3‐dihydro‐1H‐1,5‐benzodiazepines were synthesized. These molecules were screened in vitro for their antifungal and antibacterial activity, and none of the tested compounds showed promising antimicrobial or antifungal activity. J. Heterocyclic Chem., 2011.     

Different molecular conformations co‐exist in each of three 2‐aryl‐N‐(1,5‐dimethyl‐3‐oxo‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐4‐yl)acetamides: hydrogen bonding in zero,one and two dimensions

4‐Antipyrine [4‐amino‐1,5‐dimethyl‐2‐phenyl‐1H‐pyrazol‐3(2H)‐one] and its derivatives exhibit a range of biological activities, including analgesic, antibacterial and anti‐inflammatory, and new examples are always of potential interest and value. 2‐(4‐Chlorophenyl)‐N‐(1,5‐dimethyl‐3‐oxo‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐4‐yl)acetamide, C₁₉H₁₈ClN₃O₂, (I), crystallizes with Z′ = 2 in the space group P, whereas its positional isomer 2‐(2‐chlorophenyl)‐N‐(1,5‐dimethyl‐3‐oxo‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐4‐yl)acetamide, (II), crystallizes with Z′ = 1 in the space group C2/c; the molecules of (II) are disordered over two sets of atomic sites having occupancies of 0.6020 (18) and 0.3980 (18). The two independent molecules of (I) adopt different molecular conformations, as do the two disorder components in (II), where the 2‐chlorophenyl substituents adopt different orientations. The molecules of (I) are linked by a combination of N—H…O and C—H…O hydrogen bonds to form centrosymmetric four‐molecule aggregates, while those of (II) are linked by the same types of hydrogen bonds forming sheets. The related compound N‐(1,5‐dimethyl‐3‐oxo‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐4‐yl)‐2‐(3‐methoxyphenyl)acetamide, C₂₀H₂₁N₃O₃, (III), is isomorphous with (I) but not strictly isostructural; again the two independent molecules adopt different molecular conformations, and the molecules are linked by N—H…O and C—H…O hydrogen bonds to form ribbons. Comparisons are made with some related structures, indicating that a hydrogen‐bonded R₂²(10) ring is the common structural motif.     

Synthesis of substituted 3‐(5‐amino‐[1,3,4]thiadiazol‐2‐yl)‐2H‐pyrano[2,3‐c]pyridin‐2‐ones

An efficient two‐step synthesis of novel 3‐(5‐amino‐[1,3,4]thiadiazol‐2‐yl)‐2H‐pyrano[2,3‐c]pyridine‐2‐ones was developed. In the first step, a new 2H‐pyrano[2,3‐c]pyridine‐3‐carboxamide 5 was prepared by Knoevenagel condensation of pyridoxal hydrochloride with cyanoacetamide. In the second step, the reaction of carboxamide 5 with a series of N⁴‐substituted thiosemicarbazides yielded a library of 35 dis crete compounds 8 {1–35} in high yields. The intermolecular recyclization mechanism leading to these products is discussed.     

A Facile One‐Pot Synthesis of Functionalized 1,5‐Dihydro‐2H‐[1]benzopyrano[2,3‐b]pyridin‐5‐ones

The highly reactive 1 : 1 intermediate generated in the reaction between dialkyl acetylenedicarboxylate (=but‐2‐ynedioic acid dialkyl ester) 4 and triphenylphosphine was trapped by 2‐amino‐4‐oxo‐4H‐1‐benzopyran‐3‐carboxaldehydes 5 to yield highly functionalized dialkyl‐1,5‐dihydro‐5‐oxo‐1‐phenyl‐2H‐[1]benzopyrano[2,3‐b]pyridine‐2,3‐dicarboxylates in high yield.     

Syntheses of some new azolopyrido‐[4′,3′:4,5]thieno[2,3‐d]pyrimidines

Diethyl 2‐[(ethoxythioxomethyl)amino]‐4,5,6,7‐tetrahydrothieno[2,3‐c]‐pyridine‐3,6‐dicarboxylate 2 , prepared from diethyl 2‐isothiocyanato‐4,5,6,7‐tetrahydrothieno[2,3‐c]pyridine‐3,6‐dicarboxylate 1 by boiling in anhydrous ethanol, was converted into pyrido[4′,3′:4,5]thieno[2,3‐d]pyrimidine derivatives 3, 4 by treatment with hydrazine hydrate. The tetracyclic systems imidazo[1,2‐a]pyrido‐[4′,3′:4,5]thieno[2,3‐d]pyrimidine 9 and pyrido[4′,3′:4,5]thieno[2,3‐d][1,3]thiazolo‐[3,2‐a]pyrimidine 10 were synthesized by the reaction of 2 with 1,2‐diaminoethane and aminoethanethiol, respectively. The hydrazino derivative 4 underwent cyclization reactions with orthoesters and nitrous acid to give the corresponding pyrido[4′,3′:4,5]thieno[2,3‐d][1,2,4]triazolo[1,5‐a]pyrimidines 5, 6 and pyrido[4′,3′:4,5]thieno[3,2‐e][1,2,3,4]tetrazolo[1,5‐a]pyrimidine 8 , respectively. Moreover, reactions of 3 with cyanogen bromide, N‐carbethoxyhydrazine, carbon disulfide, and ethylchloroformate resulted in the formation of the new pyrido[4′,3′:4,5]thieno[2,3‐d][1,3,4]thiadiazolo[3,2‐a]pyrimidine derivatives 12–15 . © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:280–286, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/hc.10030     

Synthesis of 3‐substituted pyrido[4′,3′:4,5]thieno[2,3‐d]pyrimidines and related fused thiazolo derivatives

Convenient syntheses of 3‐substituted ethyl 4‐oxo‐2‐thioxo‐1,2,3,4,5,6,7,8‐octahydropyrid[4′,3′:4,5]thieno[2,3‐d]pyrimidine‐7‐carboxylates 3a, b, 6, 11–13 , ethyl 3‐methyl‐5‐oxo‐2,3,6,9‐tetrahydro‐5 H‐pyrido[4′,3′:4,5]thieno[2,3‐d][1,3]thiazolo[3,2‐a]pyrimidine‐8‐7H‐carboxylate ( 4 ), and ethyl 2‐methyl‐5‐oxo‐2,3,6,9‐tetrahydro‐5H‐pyrido[4′,3′:4,5]thieno[2, 3‐d][1,3]thiazolo[3,2‐a]pyrimidine‐8[7H]carboxylate ( 8 ) from diethyl 2‐isothiocyanato‐4,5,6,7‐tetrahythieno[2,3‐c]pyridine‐3,6‐dicarboxylate ( 1 ) are reported. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:201–207, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10131