STEREOSELECTIVE SYNTHESIS OF METHYL TETRA-0-METHYL a-AND P-D-GLUCO-AND MANNOPYRANOSIDES
نویسندگان: ثبت نشده
چکیده مقاله:
Methyl tetra - 0-methyl- ?-D- glucopyranoside is stereoselectively prepared from tetramethyl-D- glucopyranose by using (MeI+NaH) in toluene (86%) or cyclohexane (85%), while its ?- isomer is best synthesized in hexamethyl phosphoramide (64%). Similarly, methyl tetra-o-methyl-?- D-mannopyranoside is synthesized in cyclohexane (80%), while its ?- isomer is predominantly prepared by (MeI+n-BuLi) in cyclohexane (98%). The ?-and ?- isomers of these glycosides were identified and quantified by G.C
منابع مشابه
stereoselective synthesis of methyl tetra-0-methyl a-and p-d-gluco-and mannopyranosides
methyl tetra - 0-methyl- ?-d- glucopyranoside is stereoselectively prepared from tetramethyl-d- glucopyranose by using (mei+nah) in toluene (86%) or cyclohexane (85%), while its ?- isomer is best synthesized in hexamethyl phosphoramide (64%). similarly, methyl tetra-o-methyl-?- d-mannopyranoside is synthesized in cyclohexane (80%), while its ?- isomer is predominantly prepared by (mei+n-buli) i...
متن کاملStereoselective total synthesis of etnangien and etnangien methyl ester.
A highly stereoselective joint total synthesis of the potent polyketide macrolide antibiotics etnangien and etnangien methyl ester was accomplished by a convergent strategy and proceeds in 23 steps (longest linear sequence). Notable synthetic features include a sequence of highly stereoselective substrate-controlled aldol reactions to set the characteristic assembly of methyl- and hydroxyl-bear...
متن کاملDesign and Synthesis of 2-Methyl and 2-Methyl-4-Nitro Imidazole Derivatives as Antifungal Agents
Two series (a and b) of N- substituted heteroaromatic compounds related to clotrimazole were synthesized. Imidazole ring of the clotrimazole was replaced by 2-methylimidazole in series a, and by 2-methyl-4-nitroimidazole in series b. O-cholortrityl moiety of clotrimazole was also replaced by trityl, mono or dimethoxy trityl. Chemical structures...
متن کاملPYRAZOLINES AND ISOXAZOLINES (I). SYNTHESIS AND ANTIMICROBIAL ACTIVITIES OF P-(1-ACYL-3-METHYL-5-ARYL-4 PYRAZOLINOYL / P-(3-METHYL-5-ARYL-4ISOXAZOLINOYL) ARSANILIC ACID
4-(acetoacetamido) arsanilic acid (II), which was then condensed with aryl aldehydes. The resulting product on reaction with hydrazine hydrate and hydroxyl amine hydrochloride yielded Pyrazolines (IV) and Isoxazolines (V), respectively. The antimicrobial activity of compounds against a number of microorganisms was evaluated. Some of these compounds showed significant antimicrobial activity
متن کاملStereoselective synthesis of [C]methyl 2-[N]amino-2-deoxy- -D-glucopyranoside derivatives
Efficient syntheses of three [C]methyl 2-[N]amino-2-deoxy-D-glucopyranoside derivatives are described. Amination of the D-glucal with (saltmen)Mn(N) proceeded with 11:1 stereoselectivity favoring the gluco configuration; subsequent methylation of the [N]lactol using [C]iodomethane and silver(I) oxide afforded the doubly labeled glucoside in high yield. This compound served as the common precurs...
متن کاملsynthesis of sulfides from alcohols and thiols in solvent-freeconditions and deoxygenation of sulfoxides
کاتالیست یک سنتز جدید برای تیواترها توصیف شده است. واکنش الکل ها با آریل، هتروآریل و آلکیل تیو ل ها درحضور 1،3،5- تری آزو- 2،4،6- تری فسفرین-2،2،4،4،6،6 هگزاکلراید ((tapc به عنوان یک کاتالیست موُثر، بازده های خوب تا عالی از تیواترها را حاصل می کند. علاوه براین، واکنش تحت شرایط بدون فلز و بدون حلال پیش می رود، بنابراین یک مکمل جالب برای روش های شناخته شده سنتز تیواترها ارائه می دهد. یک مکانیسم ا...
15 صفحه اولمنابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ذخیره در منابع من قبلا به منابع من ذحیره شده{@ msg_add @}
عنوان ژورنال
دوره 3 شماره 1
صفحات -
تاریخ انتشار 1992-06-01
با دنبال کردن یک ژورنال هنگامی که شماره جدید این ژورنال منتشر می شود به شما از طریق ایمیل اطلاع داده می شود.
میزبانی شده توسط پلتفرم ابری doprax.com
copyright © 2015-2023