Jianrong Gao

One-pot synthesis of 3-(2'-Benzoxazole)-2H-1-Benzopyran-2-One Derivatives with Benzoic Acid Catalysis

A novel one-pot synthesis method of 3-heterocycle substitutued coumarin derivatives was reported. 3-(2-benzoxazole)2H-l-benzopyran-2-one derivatives were synthesized from substituted salicylaldehydes, o-aminophenols and ethyl cyanoacetate in n-butanol under the benzoic acid catalysis in one-pot reaction. This one-pot synthesis has a wide substrate scope and the salicylaldehydes with electron-donating group gave good yields. The coumarin derivatives were obtained with high purity and good yields with the simple filtration and characterized by Ή NMR and MS. The possible mechanism was presumed. This reaction was characterized by mild acid catalysis, short reaction time, simple experimental procedure and high product purity.

X-ray structure of 1,3,4-tri-O-acetyl-2-deoxy-β-d-erythro-pentopyranose

Peracetylated 2-deoxy-d-erythro-pentose (2-deoxy-d-ribose) was synthesized through the acetylation of 2-deoxy-d-ribose with acetic anhydride in pyridine, and the products (including all four ring forms) exist in form of either a white solid or a syrup. A single crystal of 1,3,4-tri-O-acetyl-2-deoxy-beta-d-erythro-pentopyranose was obtained from the syrup and its structure was determined by X-ray diffraction. The crystal adopts the (1)C(4) conformation, presenting an orthorhombic system, space group P2(1)2(1)2(1) with Z=4, unit cell dimensions a=7.2274 (3)A, b=8.0938 (5)A, and c=22.0517 (11)A.