A new method for the preparation of diazomethane

Boer, Th. J. de; Backer, H. J.

doi:10.1002/recl.19540730308

Cited by 313 publications

(42 citation statements)

References 28 publications

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“…The magnetically stirred solution of 1.14 g (5.75 mmol) of thiobenzophenone (1) [35] in 20 mL of THF was cooled to Ϫ78°C (acetone/ CO 2 bath) under N 2 ; 6 mL of ഠ 1.0  diazomethane [36] in THF was introduced slowly so as to diminish the increase of temperature. When the color of the dark-blue solution lightened, the residual diazomethane solution was added dropwise.…”

Section: 5-dihydro-22-diphenyl-134-thiadiazole (8) and Thiobenzomentioning

confidence: 99%

The Formation of 1,3-Dithiolanes from Aromatic Thioketones and Diazomethane − The Mechanism of the Schönberg Reaction

Huisgen¹,

Kalvinsch

et al. 2000

Eur. J. Org. Chem.

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Reactions of diaryl thioketones with diazomethane at room temperature afford 4,4,5,5‐tetraaryl‐1,3‐dithiolanes; the scope of this surprising 2:1 interaction has been studied for decades (Schönberg Reaction). The clue to the mechanism was our observation that the stoichiometry is 1:1 at −78 °C, and 2,5‐dihydro‐2,2‐diaryl‐1,3,4‐thiadiazoles are formed as primary [2+3] cycloadducts. They lose N2 at −45 °C in first‐order reactions generating diaryl thioketone S‐methylides which can be intercepted by thioketones (→1,3‐dithiolanes), multiple CC bonds, or acids HX. In the absence of trapping reagents, the elusive intermediates either dimerize furnishing 2,2,3,3‐tetraaryl‐1,4‐dithianes or give rise to 2,2‐diarylthiiranes by electrocyclization. Beyond thiobenzophenone and diazomethane, our main model reaction, the studies involve fluorene‐9‐thione, 4,4‐dimethoxy‐ and 4,4‐dichlorothiobenzophenone. The ring of 2,5‐dihydro‐2,2‐diphenyl‐1,3,4‐thiadiazole (8) is opened by LDA at −78 °C and derivatives of anion 12 are obtained. − In summa: The Schönberg reaction consists of two 1,3‐dipolar cycloadditions, linked by a 1,3‐dipolar cycloreversion.

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Section: 5-dihydro-22-diphenyl-134-thiadiazole (8) and Thiobenzomentioning

confidence: 99%

The Formation of 1,3-Dithiolanes from Aromatic Thioketones and Diazomethane − The Mechanism of the Schönberg Reaction

Huisgen¹,

Kalvinsch

et al. 2000

Eur. J. Org. Chem.

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“…Esterification of phospholipids was performed by dissolving the sample in an ethereal solution of diazomethane freshly prepared from A'-methyl-A'-tosylnitrosamide [15]. The solution was allowed to stand in an ice bucket for 30 min and was then evaporated in vucuo.…”

Section: Preparation Qf Drrivativesmentioning

confidence: 99%

Transfer of Bovine J-Blood-Group Determinant onto Erythrocytes: Isolation and Identification of a Blocker

Stephan

Thiele

1978

Eur J Biochem

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The bovine J-blood-group determinant is transferred from a serum glycoprotein to an erythrocyte membrane lipid by incubation in vitro. This transfer is inhibited by a lipid (called 'blocker') occurring in bovine and human serum, in other bovine and human tissues, yeast and plant tissues.The blocker was isolated from bovine spleen and identified as phosphatidylserine. Moreover, phosphatidylinositol acts as a blocker, while a variety of other phospholipids, glycosphingolipids and neutral lipids have no function as blockers. Mild alkaline deacylation deletes the blocker activity of both phosphatidylserine and phosphatidylinositol. Methyl esters of these phospholipids, or exchange of the amino group for a hydroxyl group in phosphatidylserine or N-benzoylation of phosphatidylserine, do not affect the blocker function. The blocker function of phosphatidylinositol is lost after periodate oxidation.The blocker reacts with the J-containing serum protein, not with the erythrocyte membrane. After preincubation of the J-positive serum protein with the blocker and reextraction of excess blocker, the serum protein remains J-positive, but is then unable to transfer the J determinant to the erythrocyte membrane.There are blood-group-active substances in various mammalian species that are primarily dissolved in the blood plasma and secondarily transferred onto the erythrocyte membranes [I 1. The bovine J-bloodgroup active substance is one of these [2]. Since the transfer of J activity from J-positive serum to Jnegative bovine erythrocytes can be studied in vitro [3,4], the bovine J blood-group system can be used as a model system for the study of exchange of carbohydrate units between plasma and erythrocyte membrane. A similar exchange may possibly occur also in various mammalian species [5,6].The J-blood-group activity of adult cattle is found in a serum glycolipid fraction [7] as well as in a serum nonlipid fraction, probably a glycoprotein [S]. It was shown recently [3,4] that the J determinant is transferred from the serum nonlipid to an erythrocyte membrane lipid by incubation in vitro. This transfer probably involves splitting of a covalent linkage at the serum glycoprotein, transfer of the J determinant (a carbohydrate unit) to a lipidic receptor at the erythrocyte membrane and forming of a new covalent linkage at a membrane glycolipid [4].It was established that the transfer of J activity from serum to erythrocyte membranes is inhibited by a substance (called 'blocker') present in bovine serum [9]. The blocker was shown to be a polar lipid 141. Isolation and identification of the blocker is described in this paper. MATERIALS AND METHODSBovine blood was obtained from the local slaughter house and classified J-negative (j") and J-positive (J"'), respectively, by testing small pilot samples of blood for J activity with anti-J serum that had been checked in international comparison tests. Spleens of J-negative cattle were also obtained from the slaughter house. Human blood (blood group 0) was obtained from the Gottingen bl...

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“…These acids were detected by prior preparation of their methyl esters which are stable and readily separate on the column. Freshly prepared diazomethane (de Boer and Backer, 1954) was used as the methylating agent, 2-3 drops being added to a portion of the extract.…”

Section: Gas-liquid Chromatographymentioning

confidence: 99%

The Non-Sporing Anaerobic Bacteria in Human Faeces

Peach

Fernandez

Johnson

et al. 1974

Journal of Medical Microbiology

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DIET has long been assumed to be one of the major determinants of the faecal flora (Dudgeon, 1926). Studies with experimental animals provide support for this hypothesis (Smith, 1965); however, studies with human faeces have provided less satisfactory evidence (Moore, Cat0 and Holdeman 1969).In a study of faecal specimens from different dietary groups in various parts of the world, we demonstrated differences in the numbers of bacteroides organisms present in faeces (Hill et al., 1971). In the present paper we report on the more detailed classification of the non-sporing anaerobes isolated in that study and during subsequent extensions of the study. MATERIALS AND METHODSSource of faeces. Stool samples were obtained from groups of people consuming a mixed western diet, in England, Scotland and the USA, and from people living on diets with a high carbohydrate content in India, Uganda and Japan. The characteristics of these groups are shown in table I. The groups contained both men and women. All were healthy individuals, mostly aged between 20 and 50. Samples from the USA came from both black and white persons.Transport and storage of specimens. Fresh samples of faeces were diluted 1 in 10 in 10% glycerol broth and immediately frozen in solid carbon dioxide or in liquid nitrogen for transport to London (Crowther, 1971). The samples were stored at -50°C.Isolation of non-sporing anaerobic bacteria. Isolation plates were seeded in an anaerobic cabinet. During the initial stages of this investigation a rigid Perspex cabinet filled with oxygen-free nitrogen (N2) containing 5% carbon dioxide (C02) was employed (Drasar, 1967). Later studies were carried out in a flexible polyvinyl cabinet filled with 5% C02 in a mixture of 90% N2 and 10% hydrogen (H2) (Aranki et al., 1969). Ten-fold dilutions of the specimens were prepared in Brain-Heart-Infusion (BHI) broth (Oxoid) containing 0.05% (w/v) cysteine hydrochloride and 0.03% sodium formaldehyde sulphoxylate as reducing agents. The diluent was heated to 100°C before being introduced into the cabinet, where it was dispensed and allowed to cool in the anaerobic environment. 0.1-ml samples of appropriate dilutions were spread on the surface of plates of Reinforced Clostridial Medium (Oxoid) with 1 % glucose (w/v), 1 % liver digest (Panmede, Paines and Byme, Greenford, England) and 10% defibrinated horse blood. In order to maintain the media in a reduced state, the plates were poured and dried in the Perspex cabinet, or stored for 3 days in the flexible cabinet. Seeded plates were packed into anaerobic jars and on removal from the cabinet the jars were re-evacuated and filled with a gas mixture containing 30% C02 and 70% H2 and incubated at 37°C for 3 days. Cold " D " catalyst was used in the anaerobic jars (Englhard Industries, Cindeford, Gloucestershire).

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A new method for the preparation of diazomethane

Abstract: Readily accessible and stable p‐tolylsulphonylmethylnitrosamide C7H7SO2N(NO)CH3 is introduced as an excellent starting material for the synthesis of diazomethane.

Cited by 313 publications

References 28 publications

The Formation of 1,3-Dithiolanes from Aromatic Thioketones and Diazomethane − The Mechanism of the Schönberg Reaction

The Formation of 1,3-Dithiolanes from Aromatic Thioketones and Diazomethane − The Mechanism of the Schönberg Reaction

Transfer of Bovine J-Blood-Group Determinant onto Erythrocytes: Isolation and Identification of a Blocker

The Non-Sporing Anaerobic Bacteria in Human Faeces

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