摘要:
The present invention provides a simple and inexpensive method for producing .alpha.-hydroxy-.beta.-aminocarboxylic acids and their esters.An ester of an N-protected .alpha.-amino acid ester is converted into a .beta.-ketosulfoxide, which is then processed with an acid to give an .alpha.-ketohemimercaptal. Next, this is acylated and then processed with a base to obtain an N-protected .alpha.-acyloxy-.beta.-amino-thioester, which is then saponified to obtain an intended compound. According to the method of the present invention, it is possible to produce .alpha.-hydroxy-.beta.-aminocarboxylic acid derivatives, which are intermediates in producing various HIV protease inhibitors, renin inhibitors and carcinostatics, from a-amino acids. The method comprises reduced reaction steps, the selectivity in the method to give the intended product is high, and the yield of the product obtained is high.
摘要:
A process for preparing 2',3'-dideoxyinosine comprising reducing a nucleoside of the formula IIIa or IIIb ##STR1## wherein R.sup.2 is hydrogen, C.sub.1-12 acyl, C.sub.1-12 alkyl, C.sub.7-8 aralkyl or a silyl protecting group; X is Cl, Br, or I; R.sub.5 is C.sub.1-12 acyl; H.sub.x is hypoxanthine; with hydrogen in the presence of a palladium catalyst; wherein said reduction is conducted in a solvent containing a base of pH 9-11 and wherein the solvent is acetonitrile, aqueous acetonitrile, aqueous ethyl acetate, or aqueous methanol.
摘要:
According to one embodiment, a lighting apparatus includes a main body including a flat thermal conduction surface. The thermal conduction surface contacts a back surface of a board. Light-emitting devices are mounted on a front surface of the board. An optical member is opposed to a peripheral part of the board on the front surface side of the board. The optical member is fastened to the main body by fastening members, to push the peripheral part of the board against the heat conduction surface of the main body.
摘要:
According to one embodiment, a lighting apparatus includes a main body including a flat thermal conduction surface. The thermal conduction surface contacts a back surface of a board. Light-emitting devices are mounted on a front surface of the board. An optical member is opposed to a peripheral part of the board on the front surface side of the board. The optical member is fastened to the main body by fastening members, to push the peripheral part of the board against the heat conduction surface of the main body.
摘要:
A lighting apparatus is provided with a plurality of light-emitting devices, a substrate, a blind member, and a reflector. The reflector is formed with a plurality of reflective surfaces corresponding to the light-emitting devices, individually. The shielding angle at which light emitted from that one of the light-emitting devices which is located on the outermost periphery is intercepted by the reflective surface corresponding to the outermost light-emitting device is greater than shielding angles at which light emitted from the light-emitting devices located inside the outermost light-emitting device is intercepted by the reflective surfaces corresponding to the inside light-emitting devices.
摘要:
2-Deoxy-L-ribose may be prepared by reacting a compound represented by formula (1) with an organometallic compound represented by formula (2) to give a compound represented by formula (3), which is then subjected to deprotection of a hydroxyl group and production of aldehyde by acid hydrolysis: wherein R1 and R2 are each independently a hydroxyl-protecting group or R1 and R2 in combination form a hydroxyl-protecting group, R3 and R4 are each independently an alkyl group, an aralkyl group, an aryl group or a silyl group or R3 and R4 in combination form an alkylene group.
摘要:
The present invention provides, as heteroaromatic compounds made functional so as to be used for nonlinear optical materials, compounds represented by the following general formula (1), and also provides polymers obtained from these and nonlinear optical parts comprising such polymers. In the formula, Ar.sup.1 and Ar.sup.2 each represents a divalent aromatic group; R.sup.1, R.sup.2 and R.sup.3 each represents an atom or a group independently selected from a hydrogen atom or an alkyl group and an aromatic group; X.sup.1 represents a monovalent organic group; n represents an integer of 2 to 12; and Z.sup.1 and Z.sup.2 each represents a group independently selected from electron attractive functional groups. ##STR1##
摘要:
The present invention provides a simple and inexpensive method for producing a-hydroxy-.beta.-aminocarboxylic acids and their esters. An ester of an N-protected .alpha.-amino acid ester is converted into a .beta.-ketosulfoxide, which is then processed with an acid to give an .alpha.-ketohemimercaptal. Next, this is acylated and then processed with a base to obtain an N-protected .alpha.-acyloxy-.beta.-amino-thioester, which is then saponified to obtain an intended compound. According to the method of the present invention, it is possible to produce .alpha.-hydroxy-.beta.-aminocarboxylic acid derivatives, which are intermediates in producing various HIV protease inhibitors, renin inhibitors and carcinostatics, from a-amino acids. The method comprises reduced reaction steps, the selectivity in the method to give the intended product is high, and the yield of the product obtained is high.
摘要:
The present invention provides a simple and inexpensive method for producing .alpha.-hydroxy-.beta.-aminocarboxylic acids and their esters. An ester of an N-protected .alpha.-amino acid ester is converted into a .beta.-ketosulfoxide, which is then processed with an acid to give an .alpha.-ketohemimercaptal. Next, this is acylated and then processed with a base to obtain an N-protected .alpha.-acyloxy-.beta.-amino-thioester, which is then saponified to obtain an intended compound. According to the method of the present invention, it is possible to produce .alpha.-hydroxy-.beta.-aminocarboxylic acid derivatives, which are intermediates in producing various HIV protease inhibitors, renin inhibitors and carcinostatics, from a-amino acids. The method comprises reduced reaction steps, the selectivity in the method to give the intended product is high, and the yield of the product obtained is high.