1,3,4-Oxadiazole 2- dimethylamino

Semenova, O. N., Galkina, O. S., Patsenker, L. D., Yermolenko, I. G., Fedyunyayeva, I. A. Experimental and theoretical investigation of the reaction of 2,5-diphenyl-1,3-oxazole and 2,5-diphenyl-1,3,4-oxadiazole dimethylamino derivatives with the Vilsmeier reagent. Functional Materials 200i, 11,67-75. 

Reaction of a hydrazide (128) with phosgeneiminium chloride (115) led to the 2-dimethylamino-l,3,4-oxadiazole (129) in 90% yield (75AG(E)806). The 1,3,4-thiadiazole system was also obtained in an analogous reaction in which the dithioimidate (130) underwent reaction with the thiohydrazide (131). Depending on the nature of X in (131), the 2-substituent in the resultant 1,3,4-thiadiazole (132) may be varied (80ZC413). Although (130)... 

The dipole moments of both 3- and 4-phenylsydnones containing dimethylamino and nitro substituents were calculated (ah initio 3-21G basis set) the magnitude increases with the electron donor attached to the phenyl ring <1995JPC1923>. Quadrupole moments, octopole moments, and polarizability of 1,2,3-oxadiazole have been determined by ab initio calculations and simple models <1996JPC8752, 1999JPC10009>. 

Electrochemical reduction of the 5-(bromodifluoromethyl)-l,2,4-oxadiazole 168 in the presence of tetrakis (dimethylamino)ethylene (TDAE) generates the 5-(difluoromethyl) anion which reacts with aldehydes to give the 5-g. 

The reaction of 5-[2-(iV,./V-dimethylamino)ethyl]-l,2,4-oxadiazole with methyl iodide forms the quaternary ammonium salt 170 (Scheme 22), which undergoes elimination in the presence of base (diisopropylethylamine (DIEA), TEA, l,8-diazabicyclo[4.3.0]undec-7-ene, etc.) to form an intermediate 5-vinyl-l,2,4-oxadiazole 171, which undergoes in situ Michael addition with nucleophiles to furnish the Michael adducts 172. As an example, also shown in Scheme 22, 3-hydroxy-pyrrolidine allows the synthesis of compound 172a in 97% yield. Mesylation followed by deprotonation of the 1,2,4-oxadiazole methylene at C-5 enables Sn2 displacement of the mesylate to give the 5-azabicycloheptyl derivative 173, which is a potent muscarinic agonist <1996JOC3228>. 

A, A-Dimethylformamide diethyl acetal serves as an aldehyde equivalent to give 5-dimethylamino-4,5-dihydro-l,2,4-oxadiazoles <86MI 404-04>. Oxadiazoles (171) (R = H) can be methylated or ben-zylated at N(4). With HCl or trichloroacetic acid compounds (171) are protonated on N(2) <73BSF2996>. 

Nitrosation of methyl 2-acylamino-3-(dimethylamino)propenoates 494 obtained from the corresponding oxazolones 493 effects the conversion of A -acylglycines to 5-substituted-l,2,4-oxadiazole-3-carboxylates 496 as shown in Scheme 7.157. ... 

Amino-hydroximino-methyl)-pyridin liefert mit Dimethylamino-trichlor-methan beim Sie-den in Acetonitril 5-Dialkylamino-3-(2-pyridyl)-l,2,4-oxadiazol (29% Schmp. 82—85°)113 ... 

Dimethylamino-phenylimino)-oxido-methyl]-2-methyl-5-phenyl-l,2,4-oxadiazol-2-onium 28% Schmp. 162 164°... 

Dimethisterone (see also Progestins Sequential oral eontraeeptives) Dimethoxane 3,3 -Dimethoxy benzidine 3,3 -Dimethoxybenzidine-4,4 -diisocyanate para-Dimethylaminoazobenzene / ara-Dimethylaminoazobenzenediazo sodium sulfonate tra 5-2-[(Dimethylamino)methylimino]-5-[2-(5-nitro-2-furyl)-vinyl]-l,3,4-oxadiazole... 

Reaction of a hydrazide with dichloromethylene-dimethyliminium chloride (also known as phosgeneimonium chloride) 597 led to the 2-dimethylamino-l,3,4-oxadiazole 598 (Scheme 268) <1973AGE806>. The 1,3,4-thiadiazole 601 was made by an analogous reaction from 599 and 600 (Scheme 269). 

As a rule, oxadiazoles and thiadiazoles are not nitrated. Reports on the production of 2-nitro-5-amino-l,3,4-thiadiazole during the nitration of 2-amino-l,3,4-thiadiaz-ole [274] proved erroneous [275], The compound obtained in this case was 2-nit-ramino-l,3,4-thiadiazole [275], There is only a single paper on the nitration of derivatives of 1,3,4-oxa- and 1,3,4-thiadiazoles [276], 2-Dimethylamino-l,3,4-oxa-and 2-dimethylamino-l,3,4-thiadiazoles react with the nitrating mixture with the formation of 2-dimethylamino-5-nitro derivatives. Aryl-substituted oxadiazoles and thiadiazoles are nitrated in the phenyl ring [277, 278],... 

The internal rotation barriers of the dimethylamino groups in substituted azoles including 5-nitro-2-dimethylamino-l,3,4-oxadiazole (AG =9 kcal/mol, 133°C) were also defined by NMR spectroscopy [523],... 

Thus, 2-imino-3-methyl-5-phenyl-l,3,4-oxadiazoline is obtained from the methylation of 2-amino-5-phenyl-l,3,4-oxadiazole with methyl iodide.61,63 Only in a sealed tube with an excess of methyl iodide is 2-methylimino-3-methyl-5-phenyl-1,3,4-oxadiazoline formed.63 The structure of the alkylated product was confirmed by its nonidentity with 2-methylamino-5-phenyl-l,3,4-oxadiazole or 2-dimethylamino-5-phenyl-l,3,4-oxadiazole which were synthesized by an independent route. 

Few pK values of 1,3,4-oxadiazoles have been measured, partly because of the poor water solubility of aromatic substituted oxadia-zoles. A pKb value of 11.63 (in water) is given for 2-amino-5-methyl-1,3,4-oxadiazole.156 2-Amino-5-phenyl-l,3,4-oxadiazole and its mono-and dimethylamino derivatives have approximate pKa values between 2.3 and 2.7 (in 50% alcohol).63 On the other hand, the pKa values of... 

Oxadiazol 3-Amino-5-(5-amino-6-chlor-3-dimethylamino-2-pyrazinyl)- E8c, 465... 

Malousaure (Dimethylamino-methylen)- -ethyl-ester-nitril E15/1, 641 (NC-CH2-COOR + Gold-Reagenz) 1,2,4-Oxadiazol... 

Glyoxylsaure -(4-dimethylamino-phenylnitron)-nitril X/4, 399 Hydrazin 2-Cyan-l-(3-phenyl-propanoyl)-X/2, 130 Imidazolidin 2-[2-Oxo-2-(3-pyridyl)-ethyliden]- E15/2, 2003 [aus S-(2-Oxo-alkyl)-cycl.-isothioharnstoffj lH-Isoindol 3-(2,2-Dimethyl-hydrazono)-l -oxo-2,3-d ihydro-E16a. 790 (N,N-Aufbau) 1,2.4-Oxadiazol... 

Isophthaisaure 2,6-Dimethyl-4-dimethylamino- -bis-nitriloxid E5, 1591 (aus Bis-oxim) Malonsaure (Amino-benzylamino-methylen)- -methylester-nitril E15/2, 2156 (CC13 - NH-R) I,3i4-Oxadiazol 5-Morpholino-2-phenyl- E8c, 573 (Ar — CO — NH-NH-CO-NR2/POCl3) Phthalazine l,4-Dihydroxy-6-pyrrolidino- E9a, 752 (subst. Phthalanhydrid + N2H4) lH-Pyrazol 5-Carboxy-l-methyl-4-(4-methyl-anilino)- E8b, 633 (4-Br -> 4-NH-Ar)... 

Oxadiazol 5-Amino-3- 2-[5-(dimethylamino-methyl)-2-furylmethylthio]-ethylamino -E8c, 462... 

DPLOOO CAS 55738-54-0 HR 3 trans-2-((DIMETHYLAMINO)METHYL-IMINO)-5-(2-(5-NITRO-2-FURYL)-VINYL)-1,3,4-OXADIAZOLE... 

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