摘要:
2-Acylfuran derivatives ##STR1## (R: alkyl, phenyl, etc.; R.sub.1 : H, alkyl) are prepared in high yield by reaction, in the presence of a boron trifluoride complex catalyst, of a furan compound ##STR2## (X: H, Cl, Br; Y: Cl, Br) or with RCOOH in the presence of (XYCHCO).sub.2 O.
摘要翻译:2-呋喃基衍生物通过在三氟化硼配合物催化剂的存在下,通过在呋喃化合物(X)(X)中的反应制备高收率的(R:烷基,苯基等; R 1:H,烷基) :H,Cl,Br; Y:Cl,Br)或与RCOOH在(XYCHCO)2 O存在下反应。
摘要:
A process for preparing an optically active cyclopentenone of the formula: ##STR1## wherein R is a hydrogen atom or a lower alkyl group and n is an integer of 4 to 8, which comprises contacting a dl-cyclopentenone ester of the formula: ##STR2## wherein R and n are each as defined above and R' is a lower alkyl group optionally substituted with halogen on an enzyme having a capability of hydrolyzing selectively either one of the d- or l-form isomer in the dl-cyclopentenone ester (II) in an aqueous medium for asymmetric hydrolysis.
摘要:
Acylaromatic compounds ##STR1## (Q: aromatic compound residue; R: straight, branched or cyclic aliphatic group, aromatic group or araliphatic group) are prepared in high yield by a reaction, in the presence of a boron trifluoride complex catalyst, of an aromatic compound with ##STR2## (X: H, Cl, Br; Y: Cl, Br) or with RCOOH in the presence of (XYCHCO).sub.2 O.
摘要:
By hydrolyzing a sulfonic acid ester or a nitric acid ester of an optically active 4-hydroxy-2-cyclopentenone, the steric inversion of the hydroxyl group at the 4-position of the cyclopentenone mentioned above is effected.4-hydroxy-2-cyclopentenone is useful as a raw material of prostaglandins (natural substance is an (R)-substance) having stimulative action to uterine muscle and vasodilator action. For instance, 4(S)-hydroxy-2-cyclopentenone can be configurationally inverted to R-isomer. Accordingly, this method is extremely meaningful in the synthesis of prostaglandins.
摘要:
A process for preparing an optically active 2-substituted or unsubstituted-4-hydroxy-2-cyclopentenone of the formula: ##STR1## wherein R is a hydrogen atom, an allyl group or a propargyl group, which comprises reacting the corresponding 2-substituted or unsubstituted-4-hydroxy-2-cyclopentenone of the formula: ##STR2## wherein R is defined above with a lactone chosen from (1R,5S)-6,6-dimethyl-4-hydroxy-3-oxabicyc lo[3.1.0]hexan-2-one or (1S,5R)-6,6-dimethyl-4-hydroxy-3-oxabicyclo[3.1.0]hexan-2-one in a molar ratio of 1.5 - 2:1 in the presence of p-toluenesulfonic acid or benzenesulfonic acid in the coexistence of an organic solvent under elimination of water as an azeotropic mixture with the organic solvent to obtain a reaction mixture comprising (1R,5S)-6,6-dimethyl-3-oxa-4(R)-[1(R)-4-oxo-2-substituted or unsubstituted-2-cyclopentenyloxy]bicyclo[3.1.0]hexan-2-one or (1S,5R)-6,6-dimethyl-3-oxa-4(S)-[1(S)-4-oxo-2-substituted or unsubstituted-2-cyclopentenyloxy]bicyclo[3.1.0]hexan-2-one of the formula: ##STR3## wherein R is as defined above, of which either one isomer is contained in a considerably larger amount than the other isomer, separating the isom er having the larger content from the reaction mix ture and hydrolyzing the separated isomer to give the optically active 2-substituted or unsubstituted-4-hydrox y-2-cyclopentenone.
摘要:
Acetone having a markedly low content of aldehydes is recovered from an aqueous rectification residue brought about by rectification of crude acetone carried out after one crude acetone having been alkali-treated or while an alkali or an aqueous solution thereof being added to the crude acetone, by mixing the aqueous rectification residue with an alkali, neutralizing the mixture to a pH of 4 to 9, and then subjecting the resulting mixture to distillation to obtain acetone as a distillate.
摘要:
A head-slider. The head-slider includes a slider, and a thin-film magnetic-recording head. The thin-film magnetic-recording head includes: a read element; a write element; a non-magnetic insulating protective layer disposed around both read and write elements; a resist disposed at a position further away from an air-bearing surface than the read element; and, a hard-material member including a material selected from the group consisting of silicon carbide and tungsten, which is disposed at a position further away from the air-bearing surface than the read element and the write element. Both an end of the resist and an end of the hard-material member overlap the write element when viewed in a stacking direction. A ratio of a distance from the air-bearing surface to a deepest end of the hard-material member to a distance from the air-bearing surface to a deepest end of the resist is at least 0.9.
摘要:
A thin-film magnetic head includes an MR element serving as a reproducing element and a recording induction coil. The MR element is disposed between a lower magnetic pole and an intermediate magnetic pole. The recording induction coil is disposed between the intermediate magnetic pole and an upper magnetic pole. At least a portion of the upper magnetic pole in the vicinity of a recording gap is formed of a material having a high saturation magnetic flux density of 1.4 T or higher. The intermediate magnetic pole is formed of a material having a high resistivity of 80 .mu..OMEGA..multidot.cm or higher.
摘要:
A novolak resin made from a carbonyl compound and a specific phenol compound, which resin has good properties, in particular, as a base resin of a photoresist.
摘要:
A process for purifying crude .beta.-naphthol obtained via an alkylnaphthalene hydroperoxide, comprising subjecting the crude .beta.-naphthol to a recrystallization treatment using (1) an aliphatic or alicyclic hydrocarbon solvent having 5 to 10 carbon atoms, or (2) a mixed solvent comprising the aliphatic or alicyclic hydrocarbon solvent and at least one other solvent selected from the group consisting of benzene, a benzene derivative, a ketone, an alcohol, an ether and an ester.