نتایج جستجو برای: 3-d]pyrimidin-3(4H)-amines
تعداد نتایج: 1826702 فیلتر نتایج به سال:
حفاظت از گروههای عاملی از مراحل اجتناب ناپذیر در سنتز آلی است، در این بین محافظت از گروههای آمینی بسیار حائز اهمیت است. روشهای متعددی از قبیل فرمیله کردن، استیله کردن، محافظت بصورت boc و موارد زیاد دیگری جهت محافظت از گروههای آمینی تاکنون گزارش شده است. از طرف دیگر توسعه و کاربرد کاتالیست ها و حلالهای دوستدار محیط زیست و مزایای واکنشهای بدون حلال همچون سرعت بالای واکنش، خالص سازی آسان، کاهش آلو...
Previously a deletion in mouse chromosome 17, T(22H), was shown to behave like a t allele of the t complex distorter gene Tcd1, and this was attributed to deletion of this locus. Seven further deletions are studied here, with the aim of narrowing the critical region in which Tcd1 must lie. One deletion, T(30H), together with three others, T(31H), T(33H), and T(36H), which extended more proximal...
The psychrophilic organism Colwellia psychrerythraea strain 34H produces extracellular polysaccharide substances to tolerate cold environments. Sedoheptulose 7-phosphate isomerase (GmhA) is essential for producing d-glycero-d-mannoheptose 7-phosphate, a key mediator in the lipopolysaccharide biosynthetic pathway. We determined the crystal structure of GmhA from C. psychrerythraea strain 34H (Cp...
sulfuric acid {[3-(3-silicapropyl)sulfanyl]propyl}ester (saspspe) is employed as a recyclable catalyst for the synthesis of α-amino nitriles. these syntheses were performed via a one-pot three-component condensation of aldehydes, amines, and trimethylsilyl cyanide under mild reaction conditions at room temperature. the catalyst could be recycled and reused several times without any loss of effi...
Direct evidence for metabolism in a variety of frozen environments has pushed temperature limits for bacterial activity to increasingly lower temperatures, so far to -20 degrees C. To date, the metabolic activities of marine psychrophilic bacteria, important components of sea-ice communities, have not been studied in laboratory culture, not in ice and not below -12 degrees C. We measured [3H]-l...
We examined the Arctic bacterium Colwellia psychrerythraea strain 34H for motility at temperatures from -1 to -15 degrees C by using transmitted-light microscopy in a temperature-controlled laboratory. The results, showing motility to -10 degrees C, indicate much lower temperatures to be permissive of motility than previously reported (5 degrees C), with implications for microbial activity in f...
A chiral phosphoric acid catalyzed asymmetric transfer hydrogenation of aromatic amines, quinolin-3-amines, was successfully developed with up to 99% ee. To supplement our previous work on the Ir-catalyzed asymmetric hydrogenation of 2-alkyl substituted quinolin-3-amines, a number of 2-aryl substituted substrates were reduced to provide a series of valuable chiral exocyclic amines with high dia...
BACKGROUND Colwellia psychrerythraea 34H is a psychrophilic bacterium able to produce docosahexaenoic acid (DHA). Polyketide synthase pathway is assumed to be responsible for DHA production in marine bacteria. RESULTS Five pfa genes from strain 34H were confirmed to be responsible for DHA formation by heterogeneous expression in Escherichia coli. The complexity of fatty acid profile of this s...
Using a-tetralone, as starting material, a series of phencyclidine analogues were synthesized. This ketone was reacted separately with ethylmagnesium bromide, P-methoxyphenylmagnesium bromide and P-methylphenylmagnesium bromide. The resultant alcohols were treated with a suspension of NaN3 and CCl3COOH in CHCl3. The azides were subsequently...
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