A new single-stage method for obtaining of betulin phenylcarbamates

A new single-stage synthesis of betulin phenylcarbamates is suggested that uses 1-phenylurea as a reagent for betulin O-carbamoylation. A chemoselectivity of hydroxyl-groups in carbamoylation of betulin with 1-phenylurea appeared to occur. Synthesized nitrogen-containing betulin derivatives - phenylcarbamates are valuable as bioactive substances.

Autoxidation Products of Betulonaldehyde

Three major degradation products resulted from the exposure of betulonaldehyde (1) to air in solution at room temperature. From HRMS and NMR data, the products, which were isolated by preparative supercritical fluid chromatography (SFC), were identified as betulonic acid (2) and C-17 hydroperoxide epimers 3 (β-OOH) and 4 (α-OOH). For 3 and 4, the H-18 multiplet pattern of the isolated products established the configuration at C-17.