摘要:
The invention relates to a novel process for stereocontrolled preparation of 1',1'-disubstituted and 1'-spiro-nucleosides of the formula I ##STR1## in which the substituents A, R.sub.8 and R.sub.9 are as defined in claim 1, and to novel intermediates and their use in this process and to processes for the preparation of the novel intermediates. The process is illustrated by the example of biologically active (+)-hydantocidin.
摘要:
A method of preparing sugar acetonides, such as for example 1,2:5,6-Di-O-isopropylidene-.alpha.-D-glucofuranose, by reacting the corresponding sugar, e.g. D-(+)-glucose, with acetone in the presence of a Lewis acid and a carboxylic acid derivative of general formula ##STR1## wherein X is a leaving group which may be readily replaced by a hydroxyl group.
摘要翻译:通过使相应的糖例如1,2-二氧杂环己烷-β-D-吡喃葡萄糖反应制备糖类丙烯酸酯,例如1,2:5,6-二-O-异亚丙基-α-D-呋喃葡萄糖的方法。 D - (+) - 葡萄糖与丙酮在路易斯酸和通式为“IMAGE”的羧酸衍生物存在下反应,其中X是可以容易地被羟基取代的离去基团。
摘要:
This invention relates to a process for the removal of an allyl or allyloxycarbonyl group from an allyl or allyloxycarbonyl group protected compound (such as an allylic ester, carbonate, carbamate, O-allyl derivatives or N-allyl derivatives), which comprises contacting the allyl or allyloxycarbonyl group protected compound with a sulfinic acid compound, in the presence of a palladium catalyst in a reaction-inert solvent. Preferably, the sulfinic acid compound is represented by the formula:X--SO.sub.2 M (I)wherein X is C.sub.1-20 alkyl, substituted C.sub.1-20 alkyl (wherein the substituent(s) are independently halo, nitro, sulfo, oxo, amino, cyano, carboxy, hydroxy or moieties derived therefrom), phenyl, substituted phenyl (wherein the substituent(s) are independently C.sub.1-3 alkyl, halo nitro, sulfo, oxo, amino, cyano, carboxy, hydroxy, acetamido or moieties derived therefrom), furyl or thienyl; and M is hydrogen, an alkali metal or ammonium salt residue. Of these, most preferred sulfinic acid compound is lithium p-toluenesulfinate, sodium p-toluenesulfinate, potassium p-toluenesulfinate, p-toluenesulfinic acid, ammonium p-toluenesulfinate, lithium benzenesulfinate, sodium benzenesulfinate, potassium benzenesulfinate, benzenesulfinic acid or ammonium benzenesulfinate. This invention is well suited to a process for the conversion of an allyl ester of 5R,6S-6-(1R-hydroxyethyl)-2-(1R-oxo-3S-thiolanylthio)-2-penem-3-carboxylic acid to 5R,6S-6-(1R-hydroxyethyl)-2-(1R-oxo-3S-thiolanylthio)-2-penem-3-carboxylic acid.
摘要:
Sulfamate derivatives having the following formula (I): ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, and R.sub.6 are as herein defined, have been found to exhibit anticonvulsant activity and are thus useful in the treatment of conditions such as epilepsy. Further, the present invention encompasses pharmaceutical compositions containing a compound of formula (I) as well as methods for their use and novel intermediates are disclosed.
摘要:
This invention provides novel cyclic acetals useful as delayed release flavorants and odorants having the general formula: ##STR1## These compounds possess no detectable flavor or odor themselves at normal temperatures and atmospheric conditions but release an aldehyde flavorant upon heating at higher temperatures. The novel cyclic acetals of the present invention may be used as flavorants in tobacco compositions or tobacco substitutes, as sustained flavorants and odorants to mask or enhance the flavors and odors of burning tobacco products, as flavor additives to microwaveable foods, and in the preparation of chewing gums.
摘要:
A substrate for measurement of .alpha.-amylase activity comprising a malto-oligo saccharide respresented by general formula (I) or (V) described below:A--Gn--B (I)A--Gn--I (V)wherein A represents: ##STR1## B represents a monosaccharide or a derivative thereof other than glucose; I represents inositol or a derivative thereof; G represents glucose; and n represents an integer of 3 to 15; in formula (II) or (III), R.sub.1 to R.sub.4 each represents a hydrogen atom, a lower alkyl group or (CH.sub.2)yCOOM (wherein y is 0, 1 or 2 and M represents a hydrogen atom or an alkali metal); and X.sub.1 to X.sub.4 each represents an oxygen atom or a sulfur atom.
摘要:
Novel intermediates and method for the chemical synthesis of N-substituted 1,5-dideoxy-1,5-imino-L-fucitol derivatives are provided. A preferred intermediate is 1,5-dideoxy-1,5-imino-3, 4-O-isopropylidene-L-fucitol which is used to prepare the HIV inhibitor 1,5-dideoxy-1,5-imino-[N-.omega.-methyl caproate]-L-fucitol. These compounds are prepared in a short synthesis from the known compound 2,3-O-isopropylidene-D-lyxono-1,4-lactone or in a multi-step synthesis from D-galactose.
摘要:
5-Amino-5-deoxy-1,2-O-isopropylidene-.alpha.-D-glucofuranose is conveniently prepared by a hydride reduction of 5-azido-5-deoxy-1,2,O-isopropylidene-.alpha.-D-glucuronolactone and can readily be converted to nojirimycin, deoxynojirimycin or homonojirimycin.
摘要:
An apparatus and a method for carrying out the dehydration reaction to produce a high boiling compound comprises charging a raw material and an organic solvent into a circulating system including a reactor, a preheater and an evaporator to cause the chemical dehydration reaction, drawing water, formed as a result of the dehydration reaction, together with the solvent in the form of vapor, compressing the vapor, effecting a heat exchange between the compressed vapor and the evaporator, dehydrating the compressed vapor by condensation, removing the dehydrated water out of the system, and returning the remaining solvent to the reactor.
摘要:
A compound represented by formula I ##STR1## wherein R is hydrogen, or ##STR2## wherein R.sup.1 is N-acylamino, N-alkylamino, N,N-dialkylamino, N-acyl-N-hydroxylamino, nitroso or the pharmaceutically acceptable salts thereof.