ABSTRACT
Industrial chemistry in the new millennium is widely adopting the concept of "Green chemistry" to meet the fundamental scientific challenges. Antihypertensive drugs include several of the most widely prescribed drugs like diuretics, beta-blockers, ACE inhibitors, calcium channel blockers, and α-1 adrenoreceptor blockers. The discovery of prazosin, with very high index of α1/α2 affinity has triggered off a renaissance of interest in α1-adrenoceptor antagonist drugs for treatment of hypertension. The three reported routes for synthesis and manufacture of the α-adrenoceptor antagonist- prazosin had some disadvantages. In present study we had developed new methods for the synthesis of prazosin by using microwave. The most important aspect is the overall yield of this process was ~25 % higher than the other reported methods excluding the use of banned substances.
ABSTRACT
Several modifications of the biphasic liquid-scintillation vial system for radiometry have been tried in order to improve the counting efficiency. The biphasic system consisted of an inner sterile vial containing medium and substrate, and an outer liquid-scintillation vial lined on the inside with filter paper impregnated with scintillation fluors and alkali. The system gave an overall counting efficiency of 14.6%. Substitution of methanolic NaOH for impregnation of the paper raised the counting efficiency to 29.1%. This could be further enhanced to 33.8% by lining only half of the outer vial with filter paper, thereby allowing improved optical transmission of scintillation light. Increasing the amount of fluor did not change the efficiency significantly. A complete interchange in the system, whereby half of the inner vial was lined with filter paper and was otherwise empty, while the outer vial contained the medium and substrate, gave the highest efficiency (36.9%). This also allowed the use of larger amounts of medium and the inoculum.
