The invention relates to a process for preparing a silane, to a process for modifying a silica with the silane, and to a modified silica. The process for preparing a silane of the formula I) comprises at least the following steps: a) providing a substance (R.sup.1).sub.oSi—R.sup.2—HNC(═O)NH-A-NH.sub.2; b) providing a substance HOC(═O)-A-S.sub.2-A-C(═O)OH; c) activating the substance from step b) through reaction with oxalyl chloride to form ClC(═O)-A-S.sub.2-A-C(═O)Cl; d) reacting at least two equivalents of the substance from step a) with one equivalent of the substance from step a), thereby obtaining a silane of the formula I); e) optionally purifying the silane of the formula I) obtained in step d)
(R.sup.1).sub.oSi—R.sup.2—HNC(═O)NH-A-HNC(═O)-A-S.sub.k-A-C(═O)NH-A-NHC(═O)—R.sup.2—Si(R.sup.1),  I)
wherein the groups A within a molecule may be identical or different and are aromatic groups.

The present invention relates to pyran-fused ring compounds, preparation methods thereof and use thereof, especially to pyran-fused ring compounds usable for preparing Halichondrin, Eribulin, or analogues thereof, preparation methods thereof and use thereof. Use of any of the compounds of formula (I) to (XIII) of the present invention in preparation of Halichondrin B, Eribulin, analogues thereof or C1-C13 moieties thereof. Provided in the present invention are intermediates usable for preparing Halichondrin B, Eribulin, or analogues thereof, especially the key product of C1-C13 moieties, preparation methods thereof and use thereof. The starting material for the synthesis pathway of the present invention is inexpensive and readily available with sustainable source and reliable quality. Since the structural characteristics of the reactants of theirself are made full use in choosing the method of constructing the chiral centers, the efficiency in the synthesis is considerably increased, the difficulty in and the risk on quality control of the product are reduced; and using a highly toxic and expensive high-valent osmium catalyst is avoided, which have the cost and environmental friendliness significantly improved.

The present invention relates to 1,3-oxathiolane-2-thione derivatives, to a method for the production thereof, and to the uses thereof. The present invention also relates to silylated polymers obtained from said 1,3-oxathiolane-2-thione derivatives, and also to formulations comprising them.

An organosilicon compound can be efficiently produced by using metallic element-containing nanoparticles such as a platinum element-containing nanoparticle having a solvent on surface as a catalyst of the hydrosilylation reaction of alkenes.

The invention relates to new intermediates in the synthesis of Eldecalcitol and to processes for the preparation of said intermediates and of Eldecalcitol.

An intermediate compound is prepared and used for the synthesis of halichondrin B, eribulin or an analog thereof, particularly a structural fragment C27-C35 thereof. The starting materials of the synthetic route are readily available, and the optical purity of the starting materials can be ensured, so that the optical purity of the structural fragment C27-C35 in halichondrin B, eribulin or the analog thereof is ensured. Steps for constructing a chiral center of the structural fragment C27-C35 feature higher diastereoselectivity and yield, in particular preparation methods of compounds of formulae (X), (XI), (XVI) and (XV). By-products of partial reactions can be removed only by recrystallization, which results in easy purification and significant reduce in cost.

The present invention relates to a sacubitril intermediate and a preparation method thereof. The sacubitril intermediate disclosed herein can be prepared by a deprotection reaction of a compound. In addition, the intermediate can be used as a raw material to synthesize sacubitril.

A process prepares a prepolymer containing a urethane group and a curable silicon-functional group, or a prepolymer of formula (IV), ##STR00001##
The prepolymer may be cured to a cross-linked polymer by ambient moisture and is therefore suitable for use as a component in a one-component sealant or adhesive composition.

The present disclosure relates to methods of carbon-carbon bond fragmentation.

A method for producing a compound (3),

##STR00001## by reacting a compound (1)

##STR00002##

having R.sup.1 and R.sup.2 representing a hydrogen atom or a monovalent hydrocarbon group wherein a case where both R.sup.1 and R.sup.2 are a hydrogen atom is excluded, with a compound (2)

##STR00003##

having R.sup.3 representing a divalent hydrocarbon group, R.sup.4 and R.sup.5 representing a monovalent hydrocarbon group, X representing a halogen atom, and m representing an integer of 0 to 2 the method comprising the steps of: using 0.1 mol or more and less than 1 mol of a compound (4)

##STR00004##

having R.sup.6 representing a divalent hydrocarbon group and A representing a single bond or the like per 1 mol of the halogen atom in the compound (2), and liquefying a mixture of hydrogen halide salts of the compounds (1) and (4) generated as a by-product to separate the mixture from the compound (3) and removing the mixture.