THE MECHANISM OF CARBOHYDRATE OXIDATION. I. d-GLUCOSE, d-MANNOSE, d-FRUCTOSE, d- AND l-ARABINOSE AND dl-GLYCERIC ALDEHYDE

Abstract

CARBOHYDRATE OXIDATION. I 3085 the solution filtered. The filtrate was cooled to 0°and very carefully neutralized with cold hydrochloric acid. The crystalline material so obtained was rapidly filtered off and washed several times with ice water; yield, 60%. The product was purified by crystallization from alcohol or preferably from benzene.Four g. of ethyl-vinyloxyethyl-barbituric acid, prepared as described above, was placed in 30 cc. of hot water, in which it is insoluble. On the addition of 2 cc. of hydrochloric acid and stirring, the solid dissolved almost immediately while the acetaldehyde formed by the hydrolysis was removed by boiling. The product crystallized on cooling and was purified by crystallization either from alcohol or water; yield of ethyl-d-hydroxyethyl-barbituric acid, 70%. Summary 1. A method for the preparation of hydroxy-substituted alkyl-barbituric acids has been described.2. The compounds so prepared may be hypnotics with properties similar to those of veronal and proponal, and should be less toxic. The result of a study of their pharmacology will be reported later.

Nuclear‐Magnetic‐Resonance Study of Aggregations and Conformations of Melanostatin and Related Peptides

“…For the C-terminal carboxyl group of N-protonated Pro-Leu-Gly, the pK, value in 'H20 is found to be 3.6 in the present study. This value may be compared with a similar case of N-protonated Gly-Pro [32]. For the truns form, about the (Gly)CO-N-(Proj bond, the carboxyl (COOH) proton participates in the intramolecular hydrogen bond of the .…”

Structure and reactivity of a sulfoximine‐stabilized chiral dilithiocarbanion

“…In particular, little structural information is available for chiral dilithio compounds [4], in contrast to chiral heteroatom-stabilized monolithiocarbanions which are better investigated [2] [3] [5]. In certain cases, a structure-reactivity-selectivity relationship has been established, which facilitates a rationalization of the stereochemical outcome in asymmetric transformations leading finally to an optimal design of the chiral reagent and an enhancement of stereocontrol [6]. Heteroatom-stabilized organic dilithio salts are known to act as dinucleophiles in multiple C-C bond formation reactions or as supernucleophiles in the reaction with poor electrophiles [l].…”

Revision of the Absolute Configuration of Salicylihalamide A through Asymmetric Total Synthesis

“…[8] The corresponding homoallyl alcohol 9, obtained in 96 % yield, was silylated followed by oxidative double-bond cleavage (72 % yield, 3 steps). Treatment of the corresponding aldehyde 10 with the in situ prepared Z-(O)-titanium enolate [9] derived from (2R)-N-(4pentenoyl)bornanesultam (11) [10] produced exclusively one diastereomeric aldol product 12 in 95 % yield. [11] Reduction of the corresponding MOM ether delivered primary alcohol 13 (75 %, 2 steps), which was further converted into 6 by tosylate formation, reduction, and fluoride-assisted liberation of the C15 alcohol (80 %, 3 steps).…”