Dideutero derivative

Comparing electrochemical behavior and biological transformations of purine bases, Japanese chemists (Yao and Musha 1974, Ohya-Nishiguchi et al. 1980) have considered the anion-radicals of purine, its 8-deutero and 6,8-dideutero derivatives. As it turned out, up to 40% of the total spin density is localized in position 6 of the purine anion-radical (see Scheme 3.7). Ohya-Nishiguchi et al. (1980) noted that such a large localized spin density is very rare in a n electron system of the purine s size and should have important application in relation to its chemical reactivity. Protonation should... 

The Clemmensen reduction of condensed 4//-thiopyrans 340 (R = H, Me) with zinc and hydrochloric acid gave tetrahydro derivatives 438.373 Triethylsilane and trifluoroacetic acid was used for analogous reductions of 4//-thiopyrans 45, 47, and 409 (R = H, Me, Et, Ph) to 453.362 3,5-Dideutero derivatives of 453 were obtained in the same way in the presence of O-deuteriotrifluoroacetic acid.362... 

By the action of phenyllithium, pyridazine is converted to adduct 100 (Table XVI), resulting from nucleophilic attack at position 3.34 The structural assignment is based upon H- and 13C-NMR, starting with pyridazine and its 4,5-dideutero derivative. The site of attachment of the phenyl group is other than that observed with the amide ion in ammonia (C-4). Analysis of the products obtained after hydrolysis and oxidation indicates the presence of nearly 5-6% of 4-phenyIpyridazine. Although this finding implies the formation of a small amount of the isomeric adduct 101, there is no NMR evidence for it. However, both isomeric adducts can be detected when the reaction is carried out in the presence of TMEDA or tetrahydrofuran at a lower temperature. The chemical shift values of adduct 101 are closely similar to those of the amino analog 29. 

Bohlmann absorption is also characteristic of the trans-fused but not of the cis-fused conformations of the 1,3-heterocyclic systems 87,135 88, ss and 89.136 Bohlmann bands are intense in the trans-syn-lrans-perhydropyrido-[l,2-c 2, l -/]pyrimidine 90,137 and these are markedly reduced in the 6,6-dideutero derivative,138 showing the contribution of the interheteroatomic C-6—Hax to the formation of Bohlmann bands in 1,3-heterocyclic systems. 

The 5-deutero and 4,6-dideutero derivatives of 1,2,3-trimethoxy-benzene were prepared by methylating the corresponding deuterated 2,6-dimethoxyphenols with dimethyl sulfate in 10% NaOH at room temperature. 

The equilibrium mixtures of 3-hydroxy-3-methyl-3,4-dihydro-lH-pyrido [2,l-c][l,4]oxazinium chloride 159a, its 4,4-dideutero derivatives 161a (06PJC1039) and those of 3-hydroxy-3-phenyl-3,4-dihydro-lH-pyrido [2,l-c][l,4]oxazinium bromide 159b and 161b (06JST36) with their ring-opened forms 160 and 162 were characterized by FTIR, 1H, 13C, and 15N NMR spectra in DMSO and D20. 

This osmabenzyne 69 could be converted into other osmabenzynes with HBF4 it is desilylated, with deutero-triflic acid it affords a dideutero-derivative, with excess bromine it produces a tetrabromo-derivative, and on longer treatment with HBF4 an aquo-complex was formed. 

Reaction of a 5-alkoxy derivative with NaBD4 gave the 5,5-dideutero derivative exclusively <87JHC25l>. Reduction of the compounds (79) with borane in THF gave the amines (81), whose oxidation with DDQ in AcOH afforded the derivatives (80) <92JMC320>. 

The third compound to be isolated from ozonations of Feists ester was V. Its NMR spectrum was of prime importance in establishing its structure. Other than the methoxy signal at 3.67 ppm, the outstanding feature of the spectrum was the presence of two sets of AB doublets with chemical shifts for the four protons at 3.33, 3.23, 2.90, and 2.72 ppm. The ratio of peak intensities was 6 1 1 1 1 for the five types of protons. In the spectrum of the dideutero derivative, the AB pattern at high field was not present, showing that these high field protons were those a to the carbomethoxy groups. 

The major features of the mass spectra of V and its dideutero derivative are presented in Table III. Although we were unable to detect the parent peak for V, the reasonable assignments in Table II, the simplicity... 

Studies of the Polonovski reaction in conformationally rigid polycyclic systems reveal the stereochemical requirements for the elimination step. For example, the 6p,7p-dideutero derivative (22) of nu-pharidine is converted on reaction with acetic anhydride into A -dehydrodeoxynupharidine (24) containing a single deuterium atom at Ca (Scheme 4). ... 

Urey-Bradley force constants have been calculated, using the vibrational frequencies of hydantoin or 2-thiohydantoin and its N-l,JV-3-dideutero derivatives.180,181... 

Mit Hilfe des 2,2-Dideutero-Derivates konnte gezeigt werden, daB die Photoreaktion unter intramolekularcm Wasserstoff-Transfer verlauft (Homologisierung der zugrundeliegenden Carbonyl-Verbindung um 4-C-Atome40-434 z.B. ... 

The molecular ion of 3-phenylbenzo[l>] thiophene gives the rearranged 1471 ion 2 prior to fragmentation.97 The mode of fragmentation of the 2,3-dideutero derivative suggested that all of the hydrogens in benzo[fo]thio-phene were randomized prior to the loss of ethyne from the molecular ion.98 However, later studies on benzo[b]thiophene-2-[13C] have shown that this randomization is undoubtedly due to carbon scrambling.99... 

The photoelectron spectra of acetylene (1) and its dideutero derivative were first reported by Baker and Tumer. A vibrational fine structure of 1830 cm is found for The first ionization energy at 11.4 eV is assigned to the ejection of electrons from the levels. Later on many derivatives, such as 2 and 3, were investigated. As anticipated, the... 

Proof that this is so follows from measurement of the proton Ri-values of the 6,6-dideutero derivative (C). 

Indirect evidence for the intermediacy of alkyne (88) rather than the less stable allene (86) in the base-promoted reaction of (84) has been gained from the observation that (85) fails to react under the same conditions (Bu OK-THF), but forms the exocyclic diene (89) at much higher temperature. However, the 4,4-dideutero derivative of 3-bromo-6,7-benzobicyclo[3.2.1]octa-2,6-diene (90) reacts with Bu OK to give the butoxy ether (91) in which H+-D+ exchange has occurred. ... 

The mechanism of aliphatic hydroxylation by cytochrome monoxygenases would appear to Involve a direct oxygen-insertion with retention of configuration. For exan le, when S-(+)-l- H-ethylbenzene was incubated with liver microsomes, the 1-phenylethanol produced in the reaction consisted of 92% of the R isomer and only 87. of the S isomer.83 pheno-barbital pretreatment diminished the stereoselectivity of this reaction. 63, 64 ihe reaction of the a a-dideutero-derivative exhibited an isotope effect of 1.8 when compared to the undeuterated substrate, consistent with an oxygen-insertion mechanism. In certain examples of aliphatic hydroxylation, however, it appears from the absence of an isotope effect with labeled substrates that the insertion reaction is not the rate-limiting step.85-67... 

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