摘要:

AbstractAcetyl‐Ruthenocene was labelled by heating Acetyl‐Ferrocene with97Rucl3. The tritium labelled compound was gained by exchange in tritium‐water at the acetyl side chain of acetyl‐ruthenocene. In a similar way acetyl‐ferrocene was labelled with

ISSN:0362-4803    

DOI:10.1002/jlcr.2580190502

出版商:John Wiley&Sons, Ltd.    

年代:1982

数据来源: WILEY

摘要:

AbstractA 20 mmole quantity of methyl‐13C fluoride at a13C‐enrichment level of 90% was prepared by a two‐step synthesis starting with methanol‐13C. The overall yield was 60% of methanol used. A series of gas‐chromatographic treatments using Ascarite, silica gel, and Chromosorb‐102 columns yielded a highly purified methyl fluoride in which the major impurities were less than 10 parts per million of carbon dioxide and 10 parts per million of meth

ISSN:0362-4803    

DOI:10.1002/jlcr.2580190503

出版商:John Wiley&Sons, Ltd.    

年代:1982

数据来源: WILEY

摘要:

AbstractThe α and β hydrogen exchange reactions catalyzed by pyridoxal have been applied to ten of the common amino acids to prepare α, β deuterated derivatives. The exchange and isolation procedure allows for numerous different samples to be processed in parallel. The deuteration at the α position range from 96 to 99% while the β deuteration levels range from 93 to 97% except for lysine (91%) which exchanges more slowly presumably due to interference of the ϵ‐amino group. The standard procedure produces approximately a gram of deuterated product for all samples except tyrosine (0.15 g) with yields from 70 to 85% using only 15 milliliters of2H2O. The procedure has been scaled up directly to 100 millimoles for the case of alanine with virtually identical deuteration and produ

ISSN:0362-4803    

DOI:10.1002/jlcr.2580190504

出版商:John Wiley&Sons, Ltd.    

年代:1982

数据来源: WILEY

摘要:

AbstractBoth 2S, 3R‐[2, 3‐2H2]‐serine5and 2S, 3S‐[3‐2H]‐serine6have been prepared from (E)‐methyl‐[2, 3.‐2H2]‐acrylate and (Z)‐ethyl‐[3‐2H]‐acrylate, respectively. The acrylate esters were converted to a mixture of isomeric bromohydrins by treatment with N‐bromoacetamide. The ratio of 2‐bromo‐3‐hydroxy species to the 2‐hydroxy‐3‐bromo isomer was approximately 3:1. Conversion to the corresponding azido alcohols by treatment with NaN3followed by catalytic reduction over Pd gave the alkyl esters of serine and isoserine. Purification and hydrolysis yielded serine in typically 20–25% yield from methyl or ethyl acrylate. Resolution was accomplished enzymatically by hog kidney acylase I treatment of the N‐acetyl derivative. Absolute configuration was determined by1H NMR and the ratio of proton intensity in the diastereotopic positions at C–3 were m

ISSN:0362-4803    

DOI:10.1002/jlcr.2580190505

出版商:John Wiley&Sons, Ltd.    

年代:1982

数据来源: WILEY

摘要:

AbstractA representative group of steroids have been labelled by exchange using ethylaluminium chloride and boron tribromide as catalyst and a trace of high specific activity tritiated water as isotope source. Careful choice of experimental conditions and a solvent inert to this exchange system ensures the production of high specific activity steroids with high radiochemical purity.

ISSN:0362-4803    

DOI:10.1002/jlcr.2580190506

出版商:John Wiley&Sons, Ltd.    

年代:1982

数据来源: WILEY

摘要:

AbstractThe synthesis of a mixture of D‐glucose‐6‐13C and 1,6‐anhydro‐β‐L‐idopyranose‐6‐13C and their resolution by column chromatography are described. The Kiliani reaction of hydrogen cyanide‐13C with 5‐aldo‐1, 2‐0‐isopropylidene‐D‐xylo‐pentofuranose afforded epimeric cyanohydrins. Rapidin situhydrolysis of the nitriles was effected at 50°C to obtain a mixture of the corresponding alduronic acids. The latter were reduced with LiAlH4. Hydrolysis of the isopropylidene groups with trifluoroacetic acid gave a mixture of glucose and anhydroidose. After chromatographic separation, the labeled carbohydrates were obtained in yields of 48% and 25%, respectively. Results of a13C NMR study of the Kiliani cya

ISSN:0362-4803    

DOI:10.1002/jlcr.2580190507

出版商:John Wiley&Sons, Ltd.    

年代:1982

数据来源: WILEY

摘要:

Abstract[Caboxamido‐14C]Cefotetan, 7α‐[4‐(carbamoyl carboxymethylene)‐1,3‐dithietan‐2‐yl][14C]carboxamido‐7α‐methoxy‐3‐(1‐methyl‐1H‐tetrazol‐5‐yl)thiomethyl‐y1)thiomethyl‐3‐cephem‐4‐carboxylic acid (IX), a new cephamycin derivative, was synthesized from bromo[1‐14C]acetic acid for metabolic studies. The results of duplicate preparation of14C‐Cefotetan are described. In the second synthesis, a new improved method was adopted. The overall radiochemical yields were 21.5 % and 26.7 %, at specific activ

ISSN:0362-4803    

DOI:10.1002/jlcr.2580190508

出版商:John Wiley&Sons, Ltd.    

年代:1982

数据来源: WILEY

摘要:

AbstractThe preparations of deuterium labelled THIP ([7, 7‐2H] 4, 5, 6, 7‐tetrahydroisoxazolo [5, 4‐c]pyridin‐3‐ol) (7) and THPO ([4, 4, 7‐2H] 4, 5, 6, 7‐tetrahydroisoxazo‐lo[4, 5‐c]pyridin‐3‐ol) (14) are described. [7, 7‐2H]‐THIP (7) was synthesized by triethylamine catalyzed exchange of hydrogen for deuterium in 3‐methoxy‐6‐nitroso‐4, 5, 6, 7‐tetrahydroisoxazolo [5, 4‐c] pyridine (5) using deuterium oxide, followed by acid catalyzed denitrosation and demethylation. A similar reaction sequence was employed for the preparation of [4, 4, 7‐2H]THPO (14), though the exchange reaction on theN‐nitroso intermediate12required strongly basic conditions. Deuterium labelled P4S (piperidine‐4‐sulphonic acid) (17) was synthesized by catalytic deuteration of pyridine‐4‐sulphonic acid (16). The structures of the deuterated compounds6, 7, 13, 14, and17were established using1H NMR spectroscop

ISSN:0362-4803    

DOI:10.1002/jlcr.2580190509

出版商:John Wiley&Sons, Ltd.    

年代:1982

数据来源: WILEY

摘要:

Abstract3‐Hydroxy‐4‐(hydroxymethyl)‐5‐(hydroxymethyl‐d2)‐2‐methylpyridine(pyridoxine‐d2) was prepared by reduction of α4‐3‐0‐isopropylidene‐5‐pyridoxic acid with lithium aluminum deuteride. Deuterium was inserted in the 2‐methyl group using base catalyzed exchange between deuterium oxide and N‐benzyl pyridoxine. Pyridoxine‐d2was converted to pyridoxal, pyridoxamine, pyridoxic acid, pyridoxine phosphate, pyridoxal phosphate, and pyridoxamine phosphate. After acetylation the nonphosphorylated forms could be analyzed by gas chromatography‐c

ISSN:0362-4803    

DOI:10.1002/jlcr.2580190510

出版商:John Wiley&Sons, Ltd.    

年代:1982

数据来源: WILEY

ISSN:0362-4803    

DOI:10.1002/jlcr.2580190501

出版商:John Wiley&Sons, Ltd.    

年代:1982

数据来源: WILEY