L-(+)-2β-Tropanyl Diphenylborinate

Abstract

IV diffusible substances, p-earboxybenzeneboronic acid and NaoBioHio, which are rapidly excreted. However, there was no appreciably elevated levels in tumor compared with blood and consequently such compounds would not appear to offer much promise in the treatment of tumors by neutron-capture irradiation.lna Experimental Section11Nitration of Phenylcarborane.-To 50 ml of fuming HN03, containing a crystal of urea and cooled to -15°, was added with stirring 5.0 g of powdered phenylcarborane.The time of addition was 30 min, and during this period the temperature was maintained between -10 and -15°. The solution was stirred an additional 30 min during which time the temperature was allowed to rise to 10°. The mixture was poured into ice-water, filtered, washed, and dried, yielding 5.6 g of crude nitro compound, mp 115-126°. Recrystallization from methanol gave two products.The less soluble one amounted to 2.7 g, mp 155-160°, and was purified by successive recrystallizations from methanol, mp 164-165°.

Boron-containing tetrapyrroles

“…57 Esters of boronic acids are notoriously unstable to hydrolysis. 64 However, organoboran compounds with a boroxazolidine ring in their structure exhibited high hydrolytic stability. This notable increase in hydrolytic stability is ascribed to the formation of a B-N coordinative bond.…”

Plio-Quaternary extensional tectonics of the Central Anatolian Plateau: a case study from the Tuz Gölü Basin, Turkey

“…8,9 Esters of boronic acids are notoriously unstable to hydrolysis. 10 However, organoboran compounds with a boroxazolidine ring in their structure exhibited high hydrolytic stability. This notable increase in hydrolytic stability is ascribed to the formation of a B-N coordinative bond.…”