[25] Preparation of thiamine derivatives and analogs

Matsukawa, Taizo; Honda, Hiroshi; Yurugi, Shojiro

doi:10.1016/0076-6879(71)18293-6

Cited by 21 publications

(9 citation statements)

References 119 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…and is estimated to be negligibly small [ 9]. We treat the Hamiltonian in the mean-field approximation, where the local constraint is relaxed to the global one:…”

Section: Model and Resultsmentioning

confidence: 99%

Néel and singlet RVB orders in the t-J model

Inaba

Matsukawa

Saitoh

et al. 1996

Physica C: Superconductivity and its Applications

View full text Add to dashboard Cite

The Néel and the singlet RVB orders of the t-J model in a 2D square lattice are studied in the slave-boson mean-field approximation. It is shown that the Néel order parameter takes the maximum value at the finite temperature and disappear at the lower temperature for a certain range of doping. It is also shown that the Néel and the singlet RVB orders coexist at low temperature.This suggests the possibility of the coexistence of the Néel and the superconducting orders. I. INTRODUCTIONIn order to make clear the mechanism of high-T c superconductivity in cuprates, it is indispensable to understand the whole phase diagram on the temperature-doping plane. Recent theoretical studies by the slave-boson mean-field theory based on the t-J model show the validities of the method and the model for high-T c cuprates [ 1− 4]. These studies, however, do not take into account the Néel order explicitly. A few works based on the same theoretical scheme study the Néel order [ 5,6]. In ref. 5 the Néel order and the singlet RVB order parameters are considered, but the bond order parameters are not treated in the self-consistent way. In ref. 6 the Néel order and the bond order parameters of spinon and holon are included. It is shown that there is a phase transition between itinerant and localized antiferromagnetism in the Néel state. But the singlet RVB order is not studied there.

show abstract

“…and is estimated to be negligibly small [ 9]. We treat the Hamiltonian in the mean-field approximation, where the local constraint is relaxed to the global one:…”

Section: Model and Resultsmentioning

confidence: 99%

Néel and singlet RVB orders in the t-J model

Inaba

Matsukawa

Saitoh

et al. 1996

Physica C: Superconductivity and its Applications

View full text Add to dashboard Cite

show abstract

“…Hydrogen gas was bubbled vigorously through a solution of 4-amino-5-(azidomethyl)-2-methoxypyrimidine, 10 (78.4 mg, 0.44 mmol), in ethanol (10 mL) containing 80 mg of 10% Pd/C. After 15 min, the catalyst was removed by filtration and the solvent was evaporated to give the product (61 mg, 0.4 mmol, 91% yield) as the free amine, which was used in the next step without further purification: 1 2′-Methoxythiamin (14). 2′-Methoxythiamin was prepared from 11 using modifications to a route previously developed for the synthesis of thiamin (14).…”

Section: -Amino-5-(hydroxymethyl)-2-methylpyrimidine (Hmp 5)mentioning

confidence: 99%

“…After 15 min, the catalyst was removed by filtration and the solvent was evaporated to give the product (61 mg, 0.4 mmol, 91% yield) as the free amine, which was used in the next step without further purification: 1 2′-Methoxythiamin (14). 2′-Methoxythiamin was prepared from 11 using modifications to a route previously developed for the synthesis of thiamin (14). To 109 mg (0.71 mmol) of 4-amino-5-(aminomethyl)-2-methoxypyrimidine were added the following in order: 1.2 mL of 75% ethanol (aqueous), 0.11 mL of 20% ammonium hydroxide, 189 mg (1.06 mmol) of 3-chloro-4-oxopentyl acetate (9), 0.28 mL of water, and 70 mg (0.92 mmol) of carbon disulfide.…”

Section: -Amino-5-(hydroxymethyl)-2-methylpyrimidine (Hmp 5)mentioning

confidence: 99%

Mechanistic Studies on Thiamin Phosphate Synthase: Evidence for a Dissociative Mechanism

2001

View full text Add to dashboard Cite

Thiamin phosphate synthase catalyzes the coupling of 4-methyl-5-(beta-hydroxyethyl)thiazole phosphate (Thz-P) and 4-amino-5-(hydroxymethyl)-2-methylpyrimidine pyrophosphate (HMP-PP) to give thiamin phosphate. In this paper, we demonstrate that 4-amino-5-(hydroxymethyl)-2-(trifluoromethyl)pyrimidine pyrophosphate (CF(3)-HMP-PP) is a very poor substrate [k(cat)(CH(3)) > 7800k(cat)(CF(3))] and that 4-amino-5-(hydroxymethyl)-2-methoxypyrimidine pyrophosphate (CH(3)O-HMP-PP) is a good substrate [k(cat)(OCH(3)) > 2.8k(cat)(CH(3))] for the enzyme. We also demonstrate that the enzyme catalyzes positional isotope exchange. These observations are consistent with a dissociative mechanism (S(N)1 like) for thiamin phosphate synthase in which the pyrimidine pyrophosphate dissociates to give a reactive pyrimidine intermediate which is then trapped by the thiazole moiety.

show abstract

“…11 The overall yield compares favorably with the less versatile synthesis of thiamin pyrophosphate from thiamin using thiamin pyrophosphokinase. This synthesis will be of use for the preparation of isotopicallylabeled thiamin pyrophosphate from the readily synthesized pyrimidine and thiazole moieties for NMR studies on thiamin-utilizing enzymes.…”

mentioning

confidence: 91%