scholarly journals A Stereospecific Synthesis of (±)-Abscisic Acid

1992 ◽  
Vol 45 (1) ◽  
pp. 179 ◽  
Author(s):  
J Cornforth ◽  
JE Hawes ◽  
R Mallaby
Keyword(s):  
Abscisic Acid ◽  
Thionyl Chloride ◽  
Acetyl Chloride ◽  
Selenium Dioxide ◽  
Stereospecific Synthesis ◽  
Lithium Aluminium Hydride ◽  
Cyclic Anhydride ◽  
Lithium Aluminium

A convenient separation of (E)- and (Z)-3-methylpent-2-enedioic acids was devised, and it was shown that with acetyl chloride or thionyl chloride the (Z)-acid yields the cyclic anhydride while the (E)-acid forms 6-chloro-4-methylpyran-2-one. The chloropyranone by conventional chemistry gave 4-methyl-6-(2′-oxopropyl)pyran-2-one which condensed with 4-methylpent-3-en-2-one in the presence of pyrrolidine, yielding 4-methyl-6-(2′,6′,6′-trimethyl-4′-oxocyclohex-2′-enyl)pyran-2-one. Oxidation with selenium dioxide or t-butyl chromate then gave 6-(1′-hydroxy-2′,6′,6′-trimethyl-4′-oxotyclohex-2′-enyl)-4-methylpyran-2-one, which on reduction by lithium aluminium hydride and reoxidation afforded (±)-abscisic acid stereospecifically.

VIII.—Some 9-Fluorenyl and 9,9′-Bifluorenyl Derivatives.

1969 ◽  
Vol 68 (2) ◽  
pp. 120-126
Author(s):  
J. M. Birnie ◽  
Neil Campbell
Keyword(s):  
Acetic Acid ◽  
Thionyl Chloride ◽  
Potassium Cyanide ◽  
New Method ◽  
Lithium Aluminium Hydride ◽  
Characteristic Absorption ◽  
Lithium Aluminium ◽  
Aluminium Trichloride

Summary9-Carbamoylfluorene with lithium aluminium hydride, 9-cyanofluorene with this reagent and aluminium trichloride, or (on one occasion) treatment of the oximes of 9-formylfluorene with thionyl chloride yield 9,9′-dicyano-9,9′-bifluorenyl. 9-Bromofluorene and ethanolic potassium cyanide yield 9-cyano-9,9′-bifluorenyl, and 9-formylfluorene when kept in ether for a month gives 9,9′-diformyl-9,9′-bifluorenyl. The so-called α-oxime of 9-formylfluorene described in the literature contains about 33 per cent of the higher melting β-oxime. Reduction of the oximes with zinc and acetic acid yields di(9-fluorenylidenemethyl)amine, previously obtained by other methods. A new method for the preparation of 9-aminomethylenefluorene is described and its structure has been confirmed. Many 9-substituted and 9,9′-disubstituted fluorenes exhibit characteristic absorption at 1920–1880 and 1960–1940 cm.−1.

Stereospecific Synthesis of (4E,10Z)- 4,10-Tetradecadienyl Acetate, the Major Sex Pheromone of Apple Leaf Miner Moth, Phyllonorycter ringoniella

2020 ◽  
Vol 17 ◽  
Author(s):  
Ramchandra Awalekar ◽  
Kishor Jagadhane ◽  
Shams Usmani ◽  
Shilpa Salunkhe ◽  
Dattatray Jamale ◽  
...  
Keyword(s):  
Double Bond ◽  
Sex Pheromone ◽  
Wittig Reaction ◽  
Leaf Miner ◽  
Stereospecific Synthesis ◽  
Lithium Aluminium Hydride ◽  
Simple Route ◽  
Lithium Aluminium ◽  
Main Component ◽  
Internal Alkyne

: The main component of the sex pheromone of many lepidopteran pests, (4E,10Z)-4,10-tetradecadienyl acetate (1) has been synthesized stereoselectively by using a simple route with 4-pentynol as a starting material. The stereoselective formation of the 4E double bond is based on the stereospecific reduction of internal alkyne with lithium aluminium hydride (LAH) while Wittig reaction was used to achieve 10Z double bond in the target pheromone component. The GC purity of the final acetate was achieved 97.87% while isomeric purities are more than 99%. The green chemistry principle shows a new concept towards for the multistep pheromone synthesis via green metrics calculations.

scholarly journals 1,1-Disilylethan, CH3CH(SiH3)2 / 1,1-Disilylethane, CH3CH(SiH3)2

1988 ◽  
Vol 43 (5) ◽  
pp. 571-573 ◽  
Author(s):  
Hubert Schmidbaur ◽  
Rudolf Hager
Keyword(s):  
Silicon Carbide ◽  
Acetyl Chloride ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Lithium Aluminium Hydride ◽  
Stable Isomer ◽  
Lithium Aluminium ◽  
Silicon Carbon ◽  
Volatile Liquid ◽  
Catalytic Hydrosilylation

Abstract 1,1-Bis(trichlorosilyl)ethane, CH3CH(SiCl3)2 (1) is readily available through catalytic hydrosilylation of vinyltrichlorosilane and silicochloroform (90% yield), or through the base-induced reduction of acetyl chloride using again silicochloroform (60%). 1 can be converted into the title compound 2 in 80% yield by lithium aluminium hydride in di-n-butylether. Compound 2 is a highly volatile liquid (bp. 40-42 °C), not spontaneously inflamable in air. which is of interest as a precursor for chemical vapour deposition of hydrogen-containing silicon/carbon alloys (a-Si, C:H) and silicon carbide. Based on thermodynamical data, it is the least stable isomer of the composition C2Si2H10.

Reactivity of 2,2-difluoro-3-methyl-3-butenal toward some O-, N- and C-nucleophiles

1985 ◽  
Vol 50 (12) ◽  
pp. 2730-2742 ◽  
Author(s):  
Ivan Veselý ◽  
Václav Dědek
Keyword(s):  
Double Bond ◽  
Acetic Anhydride ◽  
Acetyl Chloride ◽  
Dimethyl Acetal ◽  
Sodium Cyanide ◽  
Acetate Anion ◽  
Cyclic Acetal ◽  
Lithium Aluminium Hydride ◽  
Spontaneous Polymerization ◽  
Lithium Aluminium

Addition of nucleophiles to 2,2-difluoro-3-methyl-3-butenal (I) is complicated by its spontaneous polymerization. Compound I afforded neither hydrate nor dimethyl acetal but reacted with ethylene glycol to give the cyclic acetal II. Reaction with acetyl chloride and acetic anhydride led to the respective acetate III and diacetate IV. Satisfactory reaction with N-nucleophiles was observed only in the case of hydroxylamine and dinitrophenylhydrazine. Diethylamine reacted with I only at 150 °C to give the reduction product VI and the ethylaldimine VII. The compound I added nitromethane and sodium cyanide (giving X and XI, respectively); the adducts or products of their reduction with lithium aluminium hydride were hydroxylated at the double bond to give analogues of alcoholic sugars with difluoromethylene group in position 3. Hydroxylation of the butenal I or the acetate III afforded 3,3-difluoro-2,4-dihydroxy-4-methyloxolane (XIX) which was prepared also by cleavage of the acetal XVIII obtained from II by hydroxylation. Addition of bromine to the double bond in III and IV gave the dibromo derivatives XV and XVI; the attempted replacement of bromine in XV and XVI by acetate anion failed. Bromination of I in aqueous medium afforded 3-bromo-2,2-difluoro-3-methyl-4-butanolide (XIV).

Fluorinated tricyclic neuroleptics with prolonged action: derivatives and analogues of 2-(4-(7-fluoro-2-isopropyl-10,11-dihydrodibenzo[b,f]thiepin-11-yl)-piperazine-1-yl)ethanol

1987 ◽  
Vol 52 (7) ◽  
pp. 1811-1833 ◽  
Author(s):  
Miroslav Protiva ◽  
Jiří Jílek ◽  
Miroslav Rajšner ◽  
Karel Šindelář ◽  
Václav Bártl ◽  
...  
Keyword(s):  
Acetyl Chloride ◽  
Decanoic Acid ◽  
Lithium Aluminium Hydride ◽  
Prolonged Action ◽  
Substitution Reactions ◽  
Lithium Aluminium ◽  
Neuroleptic Agent ◽  
Depot Neuroleptic ◽  
New Compounds ◽  
Pharmacological Testing

The preparation of 4-fluoro-2-nitrobenzonitrile (V), an intermediate in the synthesis of the title compound I, from 4-fluoro-2-nitroaniline via 5-fluoro-2-iodonitrobenzene (VII) was elaborated. Syntheses of 1,1,1,3,3,3-hexadeutero-2-propyl (XX) and 1,3,4-trideutero (XXVIII) analogues of compound I from hexadeuteroacetone, and pentadeuterobromobenzene, respectively, were carried out. Compound I was esterified with acetic anhydride, decanoic acid and 3,4,5-trimethoxybenzoyl chloride to give the esters II-IV. Acylation of compound XXX with acetyl chloride, 4-fluorophenoxyacetyl chloride and (4-fluorophenylthio)acetyl chloride and the following reduction of the amides with lithium aluminium hydride gave compounds XXXII, XXXIX and XL. Substitution reactions of 11-chloro-7-fluoro-2-isopropyl-10,11-dihydrodibenzo[b,f]thiepin with the corresponding N-monosubstituted piperazines resulted in compounds XXXIII-XXXV, XXXVII, XXXVIII, XLI and XLII. Alkylation of XXX with 2-(2-chloroethyl)-1,3-dioxolane afforded compound XXXVI. Pharmacological testing of the new compounds, derivatives and analogues of the neuroleptic agent isofloxythepin (I), for discoordinating and cataleptic activities, showed especially for compounds II, XXXIV and XXXVI very intensive and long-lasting effects. The decanoate III has properties of a depot neuroleptic agent.

Convenient Synthesis of (Z)-7- and (E)-9-dodecene-1-yl Acetate, Components of Some Lepidoptera Insect Sex Pheromone

2017 ◽  
Vol 68 (1) ◽  
pp. 180-185
Author(s):  
Adriana Maria Andreica ◽  
Lucia Gansca ◽  
Irina Ciotlaus ◽  
Ioan Oprean
Keyword(s):  
Sex Pheromone ◽  
Coupling Reaction ◽  
Coupling Scheme ◽  
Lithium Aluminium Hydride ◽  
Terminal Alkyne ◽  
Mercury Derivative ◽  
Lithium Aluminium ◽  
Convenient Synthesis ◽  
Practical Synthesis ◽  
Insect Sex

Were developed new and practical synthesis of (Z)-7-dodecene-1-yl acetate and (E)-9-dodecene-1-yl acetate. The routes involve, as the key step, the use of the mercury derivative of the terminal-alkyne w-functionalised as intermediate. The synthesis of (Z)-7-dodecene-1-yl acetate was based on a C6+C2=C8 and C8+C4=C12 coupling scheme, starting from 1,6-hexane-diol. The first coupling reaction took place between 1-tert-butoxy-6-bromo-hexane and lithium acetylide-ethylendiamine complex obtaining 1-tert-butoxy-oct-7-yne, which is transformed in di[tert-butoxy-oct-7-yne]mercury. The mercury derivative was directly lithiated and then alkylated with 1-bromobutane obtaining 1-tert-butoxy-dodec-7-yne. After acetylation and reduction with lithium aluminium hydride of 7-dodecyne-1-yl acetate gave (Z)-7-dodecene-1-yl acetate with 96 % purity. The synthesis of (E)-9-dodecene-1-yl acetate was based on a C8+C2=C10 and C10+C2=C12 coupling scheme, starting from 1,8-octane-diol. The first coupling reaction took place between 1-tert-butoxy-8-bromo-octane and lithium acetylide-ethylendiamine complex obtaining 1-tert-butoxy-dec-9-yne, which is transformed in di[tert-butoxy-dec-9-yne]mercury. The mercury derivative was directly lithiated and then alkylated with 1-bromoethane obtaining 1-tert-butoxy-dodec-9-yne. After reduction with lithium aluminium hydride of 1-tert-butoxy-(E)-9-dodecene and acetylation was obtained (E)-9-dodecene-1-yl acetate with 97 % purity.

3-(s-Hydrindacen-4-yl)propylamines and 4-(s-hydrindacen-4-yl)butylamines; Synthesis and pharmacological screening

1981 ◽  
Vol 46 (8) ◽  
pp. 1800-1807 ◽  
Author(s):  
Zdeněk Vejdělek ◽  
Marie Bartošová ◽  
Miroslav Protiva
Keyword(s):  
Malonic Acid ◽  
Local Anaesthetics ◽  
Lithium Aluminium Hydride ◽  
Spasmolytic Activity ◽  
Lithium Aluminium ◽  
Malonic Acid Derivatives ◽  
Pharmacological Screening ◽  
Hydroxyethyl Piperazine

4-Chloromethyl-s-hydrindacene (VIIa) was transformed via the malonic acid derivatives VIIIa and IXa to the acid Xb which afforded in four steps the homological acid Xc. Reactions of chlorides of both acids (XIbc ) with dimethylamine, 1-methylpiperazine and 1-(2-hydroxyethyl)piperazine led to the amides XIIbc-XIVbc which were reduced with lithium aluminium hydride to the title compounds IVcd-VIcd. The amines obtained show central neuroleptic effects only in subtoxic doses; they are also potent local anaesthetics and have significant spasmolytic activity of the neurotropic as well as musculotropic type.

Substituted N,N-Dimethyl-3-(phenylthio)- and -4-(phenylthio)benzylamines

1992 ◽  
Vol 57 (1) ◽  
pp. 194-203 ◽  
Author(s):  
Karel Šindelář ◽  
Vojtěch Kmoníček ◽  
Marta Hrubantová ◽  
Zdeněk Polívka
Keyword(s):  
Serotonin Receptors ◽  
Hydrobromic Acid ◽  
Antidepressant Activity ◽  
Benzoic Acids ◽  
Lithium Aluminium Hydride ◽  
Acid Chlorides ◽  
Activity Inhibition ◽  
Lithium Aluminium ◽  
The Brain

(Arylthio)benzoic acids IIa - IIe and VIb - VId were transformed via the acid chlorides to the N,N-dimethylamides which were reduced either with diborane "in situ" or with lithium aluminium hydride to N,N-dimethyl-(arylthio)benzylamines Ia - Ie and Vb - Vd. Leuckart reaction of the aldehydes IX and X with dimethylformamide and formic acid afforded directly the amines Va and Ve. Demethylation of the methoxy compounds Ia and Ve with hydrobromic acid resulted in the phenolic amines If and Vf. The most interesting N,N-dimethyl-4-(phenylthio)benzylamine (Va) hydrochloride showed affinity to cholinergic and 5-HT2 serotonin receptors in the rat brain and some properties considered indicative of antidepressant activity (inhibition of serotonin re-uptake in the brain and potentiation of yohimbine toxicity in mice).

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