摘要:
Methods and novel intermediates of the formula: wherein R6 and R7 are lower alkyl or benzyl or R6 and R7 taken together are —CH2CH2—, —CH2CH2CH2— or —CH2CH2CH2CH2CH2—, R8 is C1-C21 alkyl or a C2-C21 monounsaturated alkenyl, which may optionally be substituted with substitution substituents independently selected from the group consisting of hydroxy, C1-C6 alkyl, C1-C6 alkoxy, C1-C6 alkoxy C1-C6 alkyl, C1-C6 alkanoyl, amino, halo, cyano, azido, oxo, mercapto and nitro, and R9 is an alcohol protecting group. The intermediates are useful for the preparation of acyclic nucleoside derivatives of the formula: where one of R1 and R2 is an amino acid acyl group and the other of R1 and R2 is a —C(O)C3-C21 saturated or monounsaturated, optionally substituted alkyl and R3 is OH or H; or a pharmaceutically acceptable salt thereof.
摘要:
Novel processes towards the synthesis of the antiviral valomaciclovir stearate in which an esterified guanine acetal is reduced to the corresponding alcohol, reacted with an activated amino acid and N-deprotected. The esterified guanine acetal is prepared from a 9-guanine derivative bearing an acyclic hydroxymethylbutylacetal. The processes are amendable to one-pot reactions.
摘要:
Methods and novel intermediates for the preparation of acyclic nucleoside derivatives of the formula: where one of R1 and R2 is an amino acid acyl group and the other of R1 and R2 is a —C(O)C3-C21 saturated or monounsaturated, optionally substituted alkyl and R3 is OH or H; or a pharmaceutically acceptable salt thereof.
摘要:
Methods and novel intermediates for the preparation of acyclic nucleoside derivatives of the formula: where one of R1 and R2 is an amino acid acyl group and the other of R1 and R2 is a —C(O)C3-C21 saturated or monounsaturated, optionally substituted alkyl and R3 is OH or H; or a pharmaceutically acceptable salt thereof.
摘要:
Methods and novel intermediates for the preparation of acyclic nucleoside derivatives of the formula: where one of R1 and R2 is an amino acid acyl group and the other of R1 and R2 is a —C(O)C3-C21 saturated or monounsaturated, optionally substituted alkyl and R3 is OH or H; or a pharmaceutically acceptable salt thereof.
摘要:
In one aspect, the invention relates to a process for preparing 6-O-substituted erythromycin derivatives comprising reacting 2′-substituted and optionally 4″-substituted 9-oxime erythromycin derivatives with an alkylating agent in the presence of a palladium catalyst and phosphine. In another aspect, the invention relates to processes for preparing 6-O-substituted erythromycin ketolides using the palladium-catalyzed alkylation reaction.
摘要:
Compounds of the Formula I where one of R1 and R2 is —C(O)CH(CH(CH3)2)NH2 or —C(O)CH(CH(CH3)CH2CH3)NH2; the other of R1 and R2 is —C(═O)C3-C21 saturated or monounsaturated, optionally substituted alkyl; and R3 is OH or H; and pharmaceutically acceptable salts thereof have utility as enhanced bioavailability antivirals against herpes and retroviral infections.
摘要:
A rapamycin analog composition includes a crystalline form of a rapamycin analog. The crystal can be a hydrate, dehydrate, solvate, or desolvate. The rapamycin analog can have a structure of Formula 1, which is optionally a prodrug, salt, derivative, or combination thereof:
摘要:
Transmission spectrometers require low levels of background light so that the signal to noise ratio is increased, and also require stable performance over wide temperature ranges. Light reflected by the transmission grating can result in increased background levels. One approach to reducing the background level is to orient the transmissive diffraction grating so that light reflected by the grating is reflected out of the diffraction plane. The temperature-induced wavelength drift of a transmission spectrometer can be due to the frame upon which the transmission grating is mounted. The wavelength drift is reduced by allowing the thermal expansion of the grating to be independent of the frame.
摘要:
The present invention relates to fiber bundles and methods for making fiber bundles. According to one embodiment of the invention, a fused fiber bundle has a terminal section ending with an endface, and includes a plurality of optical fibers, each of the optical fibers having a terminal segment ending with a proximal end, and a distal end; and a cellular holding structure, the cellular holding structure including a cellular web portion having a plurality of longitudinal cells arranged substantially in parallel and surrounded by a web material; and a tube portion surrounding the cellular web portion. The terminal segments of the optical fibers are arranged substantially in parallel, and the terminal segment of each optical fiber is disposed in a longitudinal cell of the cellular holding structure and substantially fused to the web material, thereby forming the terminal section of the fused fiber bundle.