Louisianin A (1) was treated with phosphoryl chloride (POC13) at 120~ 125°C3) to obtain chloro derivative (2) in 86% yield. 2 was reduced by Zn-AcOH at 50°C4) to afford 3 (52% yield) and 4 (35% yield). Furthermore, under the same condition, 3 was dechlorinated to give 4 in 48% yield. Moreover, 4 was oxidized in the treatment of CrO3-pyridine5) to obtain louisianin C (5) in 75% yield. Finally, 5...

In this thesis, mechanistic and synthetic studies on transformations of Hphosphonates into DNA analogues containing P-S or P-C bonds are described. Configurational stability of dinucleoside H-phosphonates and the stereochemical course of their sulfurisation in the presence of 1,8diazabicyclo[5.4.0]undec-7-ene (DBU) were investigated. In light of these studies, the reported stereoselective sulfu...

1-alkyl aryl-5-amino-4-(cyanoformimidoyl)imidazoles 4 were reacted with malononitrile and 2-amino-1,1,3-propenetricarbonitrile under mild experimental conditions, which led to 5-amino-3-(substituted benzyl)-6,7-dicyano-3H-imidazo[4,5-b]pyridines 5 and 6,8-diamino-3-(4-substituted benzyl)-3H-imidazo[4,5-b]-1,8-naphthyridine-7,9-dicarbonitrile 6, respectively, when the reaction was carried out in...

Organocatalysis for polymer chemistry has become a subject of significant interest in the last two decades. In this contribution, we have studied evolution microstructure poly(L-lactide) solution toluene at 105 °C presence various organocatalysts. Weak bases such as triethylamine and DMAP (4-dimethylaminopyridine) lead to low extent epimerization chain scission reaction. The DBU (1,8-diazabicyc...

A new series of amphiphilic α-cyclodextrins were synthesized by grafting N-acylated amino acids [valine, leucine, phenylalanine, methionine, and tryptophan (3a-e)] to the primary hydroxyl groups via ester bond formation. The synthetic pathway involves selective hexa-bromination of the primary hydroxyls followed by per-substitution with the carboxylate moiety of the N-acetyl residues in the pres...

Growing attention in developing new N-heterocyclic carbene (NHC)-mediated reactions involving homoenolate intermediates has prompted our interest in exploring the mechanistic details of the related reactions. In this work, we carried out a detailed theoretical study for the NHC-catalyzed annulation reaction of cinnamaldehyde (A) and benzodi(enone) (B) in the presence of 1,8-diazabicyclo[5.4.0]u...

A novel and convenient copper (II) bromide and 1,8-diazabicyclo[5.4.1]undec-7-ene (DBU) or 1,10-phenanthroline catalysis protocol for the construction of α-alkyl-β-keto sulfones via C(sp(3))-H bond functionalization followed by C(sp(3))-S bond formation between aryl ketones and sodium sulfinates at room temperature has been developed. This method is applicable to a wide range of aryl ketones an...

Reaction of the amino acid D-phenylalanine ethyl ester (4) with cinnamaldehyde gave chiral Schiff base 5, which underwent an asymmetric Staudinger [2+2] cycloaddition reaction with phthalimidoacetyl chloride to give the monocyclic beta-lactam 6 as a single stereoisomer. Ozonolysis of 6 followed by reduction with lithium aluminum tri(tert-butoxy) hydride afforded the hydroxymethyl beta-lactam 8....