Study of photopolymers. XVI. Novel syntheses of the polymers with azidonitrobenzoyl groups and their photochemical and thermochemical reactions

Poly-2-(2-azido-5-nitrobenzoyloxy)ethylmethacrylate (P-II-A) and poly-2-(4-azido-3-nitrobenzoyloxy)ethylmethacrylate (P-II-B) were synthesized from the reactions of 2-hydroxyethylmethacrylate with 2-chloro-5-nitrobenzoic acid and 4-chloro-3-nitrobenzoic acid, respectively, by substitution reactions of sodium azide with the corresponding chloronitrobenzoyl group. In addition, the degradation reaction of the 2-azido-5-nitrobenzoyl group in P-II-A and the transformation of the 4-azido-3-nitrobenzoyl group to 5-carboxylbenzofurazane-1-oxide ring in P-II-B by irradiation with ultraviolet (UV) light or by heating were investigated in detail. In the photochemical reaction the reaction of the azide group in P-II-A was affected by the presence of a spacer in the polymer chain. Moreover, in the thermochemical reaction the rates of the reactions of azide groups in P-II-A and P-II-B were controlled by the facility of molecular motion and the conformation of polymer chains.     

The first syntheses of enantiopure 2,2'-biindoline

The first two syntheses of chiral 2,2'-biindoline are reported either in five steps from 2,2'-bioxirane, or three steps from 2,2'-biaziridine, both with exceptional enantiopurity.     

Novel syntheses of hexahydropyrimidines and tetrahydroquinazolines

1-Benzotriazolylmethyl-3-propylhexahydropyrimidine (1) and 1,3-bis(1H-1,2,3-benzotriazol-1-ylmethyl)-1,2,3,4-tetrahydroquinazoline (3) were readily prepared by reactions of N-propyl-1,3-propanediamine or 2-aminobenzylamine with benzotriazole and formaldehyde, respectively. Intermediate 1 reacted with alkyl and aryl Grignard reagents to produce N,N'-unsymmetrically substituted hexahydropyrimidines 2a,b in 90 and 92% yields, respectively. Nucleophilic substitutions of 3 with Grignard reagents, allylsilane, and triethyl phosphite gave N,N'-disubstituted 1,2,3,4-tetrahydroquinazolines 4a-f, 5, and 6 in good to excellent yields. Successive treatment of 3 with two different Grignard reagents in one-pot reaction led regiospecifically to N,N'-unsymmetrically substituted tetrahydroquinazoline derivatives 8a,b.     

Novel syntheses of hydantoin derivativesK

N-Substituted hydantoin derivatives have been synthesized by the condensation of an α-amino acid derivative, a primary amine and diphenyl carbonate. The method has been applied to the synthesis of hydantoin derivatives with two hydroxyl and/or carboxyl groups.     

Novel syntheses of 1,3,3-trinitroazetidine

Alternative methods for the synthesis of 1,3,3-trinitroazetidine (TNAZ) from epichlorohydrin, and benzhydrylamine have been developed. These approaches employ N-sulfonyl-3-(hydroxyimino)azetidines as penultimate intermediates and represent an improvement over previously published methods which require either diazo containing intermediates or involve low yielding procedures. Parallel methods employing N-benzhydryl- and N-benzyl-3-(hydroxyimino)azetidine were also investigated as alternate routes to TNAZ.     

Thiazoles in organic synthesis. Novel syntheses of menthanes and eremophilanes

Acetylcnic thiazoles of proper design have been shown to undergo an intramolecular Diels-Alder reaction leading to fused-ring thiophene derivatives. When appropriately substituted, these latter materials can be readily converted to terpenes of the menthane and eremophilane class by Raney-nickel desulfurization     

Novel syntheses of pyrrolone and pyrrolopyridine derivatives

4-Arylmethylene-2-phenyl-2-oxazolin-5-ones 1a , b reacted with some active methylene reagents to afford pyrrolidine-3,5-dione, pyrrolo[2,3-b]pyridine and pyrrolinone derivatives. The cinnamate ester, obtained from 1a and sodium ethoxide, could be converted into a pyrrolidinone derivative having an active methylene group. This compound coupled with diazonium salts to afford the corresponding azo coupling products.     

The stereoselective syntheses and reactions of 5,6-epoxy-perhydroisoindolines

Stereo-selective syntheses of 2,5,6-trisubstituted perhydroisoindolines are achieved by preparation of the three diastereoisomeric 5,6-epoxy-perhydroisoindolines and their reactions with nucleophiles, e.g. amines. The transformation of trans-amino alcohols obtained in this way into cis-amino alcohols is described.     

Catalytic asymmetric reactions in alkaloid and terpenoid syntheses

Catalytic asymmetric induction is one of the most important methods in current synthetic organic chemistry for designing efficient and attractive synthetic routes. The efficient total synthesis of a natural product can be achieved through the identification of appropriate method and strategy. This Letter introduces the catalytic asymmetric syntheses of alkaloids and terpenoids based on an overview of four recently reported types of asymmetric reaction: (1) asymmetric decarboxylative allylation, (2) organocatalytic cascade reaction, (3) polyene cyclization, and (4) asymmetric [2+2]-photocycloaddition catalyzed by a chiral Lewis acid.