Synthesis of benzo[b][1,4]thiazepines by the reaction of 3‐aryl‐1‐(3‐coumarinyl)propen‐1‐ones with 2‐aminothiophenol

3‐(2‐Aryl‐2,3‐dihydro‐benzo[b][1,4]thiazepin‐4‐yl)chromen‐2‐ones ( 2a, e, f ) and (Z)‐3‐(2,3‐dihydro‐2‐arylbenzo[b][1,4]thiazepin‐4(5H)‐ylidene)chroman‐2‐ones ( 3a‐f ) have been synthesized by the reaction of 3‐aryl‐1‐(3‐coumarinyl)propen‐1‐ones ( 1a‐f ) with 2‐aminothiophenol in a hot mixture of toluene and acetic acid. Structures of all new compounds and their complete ¹H and ¹³C assignments were achieved applying different one‐ and two‐dimensional nmr experiments in combination with various spectroscopic techniques.     

Synthesis of optically active N‐protected α‐aminoketones and α‐amino alcohols

A series of optically active N‐protected α‐aminoketones were synthesized via the Grignard reaction of the Weinreb amides of the N‐tert‐butoxycarbonyl amino acids. Reduction of the α‐aminoketones by sodium borohydride resulted in the corresponding 1,2‐amino alcohols. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:603–606, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10195     

Synthesis of optically active oligonaphthalenes via second-order asymmetric transformation

Synthesis of numerous optically active rod-shaped oligo(2,3-dioxyfunctionalized)naphthalenes connected at their 1,4-positions was achieved using oxidative coupling under CuCl2/alpha-methylbenzylamine conditions by second-order asymmetric transformation. We believe this method is practical and should contribute to the field of material science.     

Synthesis and NMR spectroscopic studies of optically active derivatives of γ‐aminobutenoic acids and 2‐amino‐pyrrolin‐4‐ones

An efficient method for the preparation of optically active derivatives of γ‐amino‐butenoic acids and their cyclic derivatives, 2‐amino‐pyrrolin‐4‐ones, from α‐amino acids is described. Partial racemization accompanies the formation of initial unsaturated γ‐amino‐β‐hydroxy esters 5–8 , as determined by chiral HPLC.     

Nickel‐Catalyzed Cross‐Coupling Reactions of o‐Carboranyl with Aryl Iodides: Facile Synthesis of 1‐Aryl‐o‐Carboranes and 1,2‐Diaryl‐o‐Carboranes

A nickel‐catalyzed arylation at the carbon center of o‐carborane cages has been developed, thus leading to the preparation of a series of 1‐aryl‐o‐carboranes and 1,2‐diaryl‐o‐carboranes in high yields upon isolation. This method represents the first example of transition metal catalyzed C,C′‐diarylation by cross‐coupling reactions of o‐carboranyl with aryl iodides.     

Synthesis of optically active polyurethanes by self‐polyaddition of tyrosine‐based monomers

The synthesis and self‐polyaddition of the optically active monomers I‐T(L )‐M and I‐T(D )‐M bearing both isocyanate and hydroxyl groups were examined. I‐T(L )‐M and I‐T(D )‐M were synthesized by reactions of L ‐ and D ‐tyrosine methyl ester, T(L )‐M and T(D )‐M, with di‐tert‐butyltricarbonate, respectively. The self‐polyaddition of I‐T(L )‐M and I‐T(D )‐M proceeded smoothly with triethylamine or tert‐butyllithium as the initiator in tetrahydrofuran, affording the optically active linear polyurethanes poly[I‐T(L )‐M] and poly[I‐T(D )‐M] with specific head‐to‐tail structures, where the number‐average molecular weights ranged from 10,000 to 20,000 in excellent yields. The optical properties suggested the idea that poly[I‐T(L )‐M] and poly[I‐T(D )‐M] should have some higher order structures. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1143–1153, 2004     

Synthesis and spectroscopic studies of optically active n‐acetyl butenoates and n‐acetyl‐2‐alkyl‐pyrrolin‐4‐ones

The synthesis of a series of optically active N‐acetyl butenoates 3–5 is described using a facile methodology. These butenoates undergo cyclization to the corresponding N‐acetyl‐2‐alkyl‐pyrrolin‐4‐ones 6,7 retaining their stereochemical integrity. The structure of the newly synthesized compounds has been elucidated through ¹H‐¹³C NMR, IR spectroscopy and their enantiomeric excesses have been measured by chiral HPLC analysis.     

Condensation products of 1‐aryl‐4‐carboxy‐ 2‐ pyrrolidinones with o‐diaminoarenes,o‐aminophenol,and their structural studies

A series of 2‐substituted benzimidazoles, benzoxazoles were synthesized by the condensation reactions of 1‐aryl‐4‐carboxy‐2‐pyrrolidinones and aromatic ortho‐diamines or ortho‐aminophenol. Alkylation of benzimidazoles with iodoalkanes led to 1‐aryl‐4‐(1‐alkyl‐1H‐benzimidazol‐2‐yl)‐2‐pyrrolidin‐ ones or 1,3‐dialkylbenzimidazolium iodides. N‐Subs‐ tituted γ‐amino acids were prepared by the hydrolysis of 1‐aryl‐4‐(1H‐benzimidazol‐2‐yl)‐2‐pyrrolidinones in sodium hydroxide solution, followed by treatment with acetic acid. The structure of the synthesized pro‐ ducts was investigated using IR and ¹H, ¹³C NMR spectra, MM2 molecular mechanics, and AM1 semi‐ empirical quantum mechanical methods. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:47–56, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20171     

Facial Synthesis of o‐Carborane‐Substituted Alkenes and Allenes by a Regioselective Ene Reaction of 1,3‐Dehydro‐o‐carborane

1,3‐Dehydro‐o‐carborane is a useful synthon for selective cage boron functionalization of o‐carboranes. It reacts readily with alkenes or alkynes to give a variety of cage B(3)‐alkenyl/allenyl o‐carboranes by ene reactions in very high yields and excellent regioselectivity. This can be ascribed to the highly polarized cage C?B multiple bond, which lowers the activation barriers of the ene reaction.     

Synthesis and properties of optically active aromatic polyimides derived from optically pure 1,1′-bi-2-naphthol

A series of new optically active aromatic polyimides containing axially dissymmetric 1,1′-binaphthalene-2,2-diyl units were prepared from optically pure (R)-(+)- or(S)-(−)-2,2′-bis(3,4-dicarboxyphenoxy)-1,1′-binaphthalene dianhydrides and various aromatic diamines via a conventional two-step procedure that included ring-opening polycondensation and chemical cyclodehydration. The optically pure isomer of dianhydride was prepared by a nucleophilic substitution of optically pure (R)-(+)- or(S)-(−)-1,1′-bi-2-naphthol with 4-nitrophthalonitrile in aprotic polar solvent and subsequent hydrolysis of the resultant tetranitrile derivatives, followed by the dehydration of the corresponding tetracarboxylic acids to obtain the dianhydrides. These polymers were readily soluble in common organic solvents such as N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and m-cresol, etc., and have glass transition temperatures of 251–296°C, and 5% weight loss occurs not lower than 480°C. The specific rotations of the optically active polyimides ranged from +196° to +263°, and the optical stability and chiroptical properties of them were also studied. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 3287–3297, 1997     

Synthesis of new optically active α,α′,β‐trisubstituted‐β‐lactones as monomers for stereoregular biopolyesters

Various optically active (4R)‐alkyloxycarbonyl‐3,3‐dialkyl‐2‐oxetanones as monomers were synthesized from L‐(S)‐malic acid in six steps to prepare a new family of stereopolyesters for biomedical applications. The synthesis began with an esterification followed of a dialkylation in the aim to introduce hydrophobic groups as methyl or reactive group as allyl. Then, a saponification has permitted to obtain the corresponding diacids that reacted with appropriate alcohols to furnish different monoesters. The last and most important step was activation of hydroxyl group of monoesters with the asymmetric carbon configuration inversion according to the Mitsunobu reaction. Thus, this reaction has provided lactones from monoesters with 100% enantiomeric excess which was confirmed by ¹H NMR and by the synthesis of corresponding isotactic and semicrystalline homopolyesters. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2586–2597     

Synthesis and spectral properties of 2‐[(o‐ and p‐substituted)aminophenyl] ‐3H‐5‐[(o‐ and p‐substituted)phenyl]‐7‐chloro‐1,4‐benzodiazepines

A series of twelve new 2‐[(o‐ and p‐substituted)aminophenyl]‐3H‐5‐[(o‐ and p‐substituted)phenyl]‐7‐chloro‐1,4‐benzodiazepines, which have possible pharmacological properties has been obtained. The synthesis was carried out following six steps. The structure of all products was corroborated by ir, ¹H nmr, ¹³C nmr and ms. In addition for the compound 2‐(o‐chloroaminophenyl)‐3H‐5‐(o‐fluorophenyl)‐7‐chloro‐1,4‐benzodiazepine 7, its structure was confirmed by X‐ray diffraction.     

Synthesis of poly(o‐cresol) by oxidative coupling polymerization of o‐cresol

The oxidative coupling polymerization of o‐cresol was investigated using various 2‐substituted pyridine/CuCl catalysts under an oxygen atmosphere, in which 2‐phenylpyridine/CuCl and 2‐(p‐tolyl)pyridine/CuCl catalysts yielded poly(o‐cresol)s with higher regioselectivity for 1,4‐coupling. These polymerizations produced branched and crosslinked polymers in the later stages of polymerization. These polymers showed good thermal properties, such as 5% weight loss temperatures of up to 406 °C and glass transition temperatures of up to 151 °C. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 878–884     

Convenient synthesis of optically active α‐hydroxyphosphinic acids

The reaction of O‐menthyl phenylphosphonite 1 with aromatic aldehydes in the presence of Me₃SiCl provided the O‐menthyl α‐hydroxyphosphinates 2 . Acidic hydrolysis of 2 gave the corresponding α‐hydroxyphosphinic acids 3 . The (+)‐enantiomer of 3a and 3b , adduct of benzaldehyde and 4‐methylbenzaldehyde respectively, were obtained via multiple recrystallization. The absolute configuration of (+)‐ 3a was determined as S by X‐ray crystallography. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:312–315, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10150     

Design and synthesis of optically active 2‐phenylimidazolecarboxamides featuring amino acid motive

Overall sixteen new, optically active carboxamides 1‐3 have been synthesized. These compounds based on the 2‐phenylimidazole and featuring amino acid residues are linked on the 4‐position by an amidic bond. Two general methods were used for their construction. Whereas the first method employs acylchlorides as a reactive species, the second one involves a condensation of mixed anhydrides with the amino acid counterparts. Actually, the second method proved to be more efficient than the first one. Carboxamides 1‐3 were preliminarily tested as N‐chelating ligands with an application in the Henry or Aldol reactions affording either poor yields or enantiomeric excesses.     

A novel optically active diblock copolymer composed of poly(ethylene glycol) and poly[N‐{o‐(4‐phenyl‐4,5‐dihydro‐1,3‐oxazol‐2‐yl)phenyl}maleimide]: Synthesis,micellization behavior,and chiroptical property

A series of optically active amphiphilic block copolymers were synthesizedby using potassium alkoxide of poly(ethylene glycol) monomethyl ether (MeOPEGO^?K⁺) to initiate the anionic polymerization of N‐{o‐(4‐phenyl‐4,5‐dihydro‐1,3‐oxazol‐2‐yl)phenyl}maleimide [(R)‐PhOPMI]. The PEG‐macroinitiators generated in situ in the reaction between MeOPEGOH and potassium naphthylide in tetrahydrofuran. The synthetic procedure may provide the PEG‐b‐PPhOPMI copolymers with well‐defined structure, as evidenced by gel permeation chromatography, ¹H NMR, FTIR, and elemental analysis. In particular, the preparation of block copolymers having a laevorotation or dextrorotation activity was accomplished by changing the feed composition. The micellization was examined for the amphiphilic block copolymers in aqueous milieu by fluorescence spectroscopy, dynamic light scattering, and circular dichroism. The results indicate that the copolymers could form regular spherical micelles with core‐shell structure when the hydrophilic component was long enough; in contrast, the copolymers containing shorter PEG segments formed aggregates in large dimension due to the considerable interaction between hydrophobic PPhOPMI components. Also, it was found that the aggregated structure of the polymeric micelles is strongly dependent on the medium nature and the polymer concentration. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1025–1033, 2008