Pummerer rearrangement using bis(p-nitrophenyl) phosphorazidate as an azidation reagent: A novel synthesis of azidomethyl sulfides

A novel method for the synthesis of azidomethyl sulfides by Pummerer rearrangement using bis(p-nitrophenyl) phosphorazidate (p-NO₂DPPA) as an azidation reagent was developed. Various methyl sulfoxides were converted into the corresponding azidomethyl sulfides. Importantly, this reaction enables the preparation of azidomethyl sulfides without the use of toxic or explosive azide sources.     

Aluminum-chloride catalyzed reaction of allylic sulfides with methyl propiolate: A novel addition reaction via an ionic [3.3] sigmatropic rearrangement

The aluminum-chloride catalyzed reaction of allylic sulfides with methyl propiolate resulted in the clean formation of novel 1:1 adducts via ionic [3.3] sigmatropic rearrangements.     

A novel rearrangement of 2(5H)-furanones

A novel rearrangement of 2(5H)-furanones is described. When refluxed in aq. Ethanolic solution in the presence of excess KOH, the 2,5-dihydro-2-oxofuran-3-carboxamides 6 underwent a novel rearrangement to the corresponding 4,5-dihydro-4-oxo-2-(phenylamino)-3-furancarboxylic acids 1 in moderate-to-excellent yields.     

A novel rearrangement of 1-(2-aminoaryl)imidazoles

6-Ethyl-2,4-bis(1H-imidazol-1-yl)pyrimidin-5-amine was found to undergo a novel rearrangement in the presence of acetic anhydride. The structure of the rearrangement product was deduced using a combination of one- and two-dimensional nmr methods. Confirmation of the structure was obtained by unambiguous synthesis of a reduced analog and establishment of the identity of this material with material prepared by reduction of the rearrangement product. Examination of three related cases indicated that the rearrangement process is significant only when both positions adjacent to the aryl amino group are substituted.     

Oxidative transformations of alkyl caryophyllanyl sulfides

Sesquiterpene sulfoxides and sulfones were synthesized in up to 56 and 74% yields, respectively. The oxidation of sulfides was accompanied by rearrangement of the epoxide fragment to allylic alcohol with subsequent oxidation. The isomerization of 4,5-epoxycaryophyllane-15-thiol afforded for the first time 4,11,11-trimethyl-8-(sulfanylmethyl)bicyclo[7.2.0]undec-3-en-5-ol in 40–45% yield.     

Dipole moments and conformations of 2-(4-pyridyl)ethyl alkyl(aryl) sulfides

Conclusions Study of the 2-(4-pyridyl)ethyl akyl sulfides has shown that these compounds exist as equilibrated mixtures of structures with trans- and gauche-oriented C-Py and C-S fragments, the content of the first making up 0.6–0.7 fraction of the whole.Translated from Izvestiya Akademii Nauk SSSR. Seriya Khimicheskaya, No. 11, pp. 2472–2475, November, 1976.The authors wish to thank A. N. Vereshchagin for valuable advice.     

微波辐射法合成丙二酸甲(乙)烷酯

丙二酸甲(乙)烷酯类是一些药物和天然产物合成的中间体,一般由丙二酸二甲(乙)酯经部分水解得到丙二酸单甲(乙)酯钠盐,再通过酸化、酰氯化和酯化反应制得[1],该方法路线较长、酰氯化反应会产生有毒尾气。羧酸(包括烷酸和芳酸)酯可由其盐和卤代烃直接反应制得[2-4],而且可利用无溶剂相转移催化的条件进一步加速反应和提高产率。微波技术用于有机合成[5-7]具有操作简便、产率高和速度快等优点。我们参考文献[2-4]方法,应用微波技术合成了标题化合物。1　实验部分1 1　仪器ＢｒｕｋｅｒＤＰＸ 300ＦＴ ＮＭＲ型核磁光谱仪,ＴＭＳ为内标;ＩＲ…     

Synthesis and transformations of some (heteroaryl)acetylazides, (heteroaryl)methyl isocyanates and alkyl (heteroaryl)methyl carbamates

The synthesis of two complex acetyl azides 6 and 10 having an heteroaryl residue bound to the acetyl group through the ring nitrogen, and their further transformations into the corresponding carbamates 7a-b and 11a-b and isocyanates 16 and 14 are described. Hydrolysis of these products results in the elimination of the substituted methyl group from the heterocyclic residue and formation of 1-unsubstituled heterocycles. A similar transformation was also observed under mass measurement conditions.     

A novel oxamide rearrangement

An efficient, base-induced rearrangement of 2-[(1,2-dioxo-2-(methylamino)ethyl)phenylamino]benzoic acid methyl ester ( 7a ) to the isomeric 2-[(1,2-dioxo-2-(phenylamino)ethyl)methylamino]benzoic acid methyl ester ( 27a ) is described. This novel rearrangement must proceed through a spiro intermediate wherein benzoate is acting as a Michael receptor. When 2-[(1,2-dioxo-2-(methylamino)ethyl)methylamino]benzoic acid methyl ester ( 28 )-an oxamide which would produce a degenerate spiro intermediate — was subjected to rearrangement conditions, the product obtained was 1,3-dimethyl-2,4-(1H,3H)quinazolinedione ( 29 ). This latter transformation may have proceeded via a benzodiazepinetrione intermediate.     

ipso-Substitution with Sodium-N-alkyl-(p-nitrobenzene)sulfonamide. A novel anionic rearrangement

Reaction of N-benzyl-N, N-di-(p-nitrobenzene)sulfonamide ( 3 ) with NaCN/HMPA at 140° affords N-benzyl-p-nitroaniline ( 4 ). The same product is obtained upon heating of the sodium salt of N-benzyl-(p-nitrobenzene)sulfonamide ( 5 ). The transformation 5 → 4 is believed to proceed via an anionic episulfonyl compound 6 .     

Molecular vibrations and force fields of alkyl sulfides: Part XV. C-S stretching vibrations of aliphatic alkyl sulfides

The C-S stretching vibrations of 28 aliphatic sulfides including one thiol are summarized, and all of the C-S stretching bands are classified into several groups. An extraordinarily low frequency associated with the ethyl group is discussed briefly.     

The Pummerer rearrangement of phenyl methyl sulphonium bis(methoxycarbonyl)-methylide

The reaction between phenyl methyl sulphonium bis(methoxycarbonyl)methylide and either acetic anhydride or benzoyl peroxide proceeds via “Pummerer” type rearrangement to afford phenyl α-acyloxymethyl sulphide. The kinetic data suggest that the rate-determining step involves SC bond cleavage after initial acylation or acyloxylation and subsequent proton removal by acyloxy anion unlike the corresponding reaction of the analogous sulphoxide with acetic anhydride in which the rate determining step is proton removal.     

A facile one-pot synthesis of alkyl aryl sulfides from aryl bromides

A convenient one-pot synthetic method for the formation of alkyl aryl sulfides from various alkyl halides and lithium aryl thiolates that are prepared in situ by direct halogen-lithium exchange is reported. In particular, the method overcomes many of the problems encountered in previous reports; it is very quick, catalyst-free, and does not involve use of unstable aryl thiols.     

Inhibitory effect of 2-(E-2-alkenoylamino)ethyl alkyl sulfides on gastric ulceration in rats. II. Structure and activity relationships of 2-(E-n or Z-n-Decenoylamino)ethyl alkyl sulfides

The analogues of 2-(E-n or Z-n-decenoylamino)ethyl carbamoylmethyl sulfide, including the modifications of sulfide portion, double bond in decenoyl chain and alkyl sulfide moiety, were synthesized and their inhibitory effects on stress-induced ulceration in rats were compared. Replacing the sulfura atom by methylene group or oxygen atom reduced the effect of potency. Saturation of the double bond in the decenoyl chain tended to reduce the anti-ulcerogenic activity in rats. There was no relationship between the position of double bond in decenoyl chain and the pharmacological activity. On the other hand, compounds with E-configuration showed stronger anti-ulcer activity than the corresponding Z-type of compounds. Among 9 kinds of S substituted alkyl groups for carbamoylmethyl, 2-(E-2-decenoylamino)ethyl 2-cyclohexylethyl sulfide showed the most potent anti-ulcerogenic activity in rats and also showed the lowest acute toxicity in mice.     

Transalkylation of alkyl aryl sulfides with alkylating agents

The reaction of methyl iodide with tert-butylphenylsulfide in DMF leads to a transalkylation that produces methylphenylsulfide. This transalkylation reaction was further studied by ¹H NMR spectroscopy. The polarity of the solvent, the electron density on the sulfur atom, and the strength of the alkylating agent (MeI, EtI, BuI, dimethyl sulfate, or dimethyl carbonate) played important roles in the reaction. The suggested mechanism of the reaction involves the formation of a dialkyl aryl sulfonium salt that subsequently eliminates the radical. This mechanism was supported by the observation of higher conversion rates for compounds with more branched alkyl groups on the sulfur atom, which may lead to the formation of more stable radicals.