3-Amino-6,7-dihydro

The H- and 3C-NMR spectra of a solution of 7 in K.NH2/NH3 measured at — 50 C are complex. It was originally suggested that in this solution a mixture of three a-adducts, 2-amino- (8), 6-amino-, and 8-amino-dihydro-1,7-naphthyridinide (9), was present.15 More detailed studies on covalent animation with 6,8-dideutero-l,7-naphthyridine have shown that this suggestion was not correct the upheld shift value of Af> = 3.12 ppm, originally assigned to H-6 in the 6-amino adduct, must be ascribed to H-5 in 9 (Figure l).16 13C-NMR spectroscopy confirms these results. In fact a mixture of only two adducts, 8 and 9, is formed when 7 is dissolved in KNH2/NH3. 

H- and 13C-NMR spectroscopy of a solution of 13 in KNH2/NH3 shows that H-l and C-l have undergone upheld shifts of 4.24 ppm and 83.7 ppm, respectively (Tables II and III).20 This is due to the formation of 1-amino-dihydro-2,6-naphthyridinide (14). Because 2,6-naphthyridine is reported to have the lowest electron density at position 11819 (Table I), the formation of cr-adduct 14 is in good agreement with these calculations. The spectrum of... 

From total n-electron density calculations, position 1 in 15 is predicted to be the most vulnerable to a charge-controlled nucleophilic attack (see Table l).18,19 Experiment agrees with these predictions, as dissolving 15 in KNH2/NH3 at — 40 C immediately leads to the formation of 1-amino-dihydro-2,7-naphthyridinide (16) as observed by the H- and 13C-NMR spectra20 (Tables II and III). On heating to room temperature no change of the NMR spectra was found. resonance stabilized by an important contribution of resonance structure (16b) as evidenced by the presence of a considerable upheld shift of C-4 and H-4. 

Oxidation of a solution of 3-alkyl(aryl)-l,2,4,5-tetrazines in liquid ammonia with permanganate proved to be an excellent route for preparing 6-amino-l,2,4,5-tetrazines (Scheme 30) (81JHC123). The covalent a-adduct, i.e., amino-dihydro-1,2,4,5-tetrazine, is intermediate, as proved by NMR spectroscopy. Based on model studies of 3-phenyl-1,6-dihydro-1,2,4,5-tetrazine, this non-isolable amino-dihydro-1,2,4,5-tetrazine has been characterized as having a homotetrazole structure A (Scheme 30) (81JOC3805). 

The H-and C-NMRspectraofasolutionof in KNH2/NH3measured at — 50 C are complex. It was originally suggested that in this solution a mixture of three (x-adducts, 2-amino- (8), 6-amino-, and 8-amino-dihydro-... 

Alkensaure-nitrile bilden mit Hydrazinen 3- und 5-Amino-dihydro-pyrazole509. Sind an der C,C-Doppelbindung eliminierbare Reste (Halogen, Organooxy, Organothio, Amino, Trichlor-methyl), werden 3- oder 5-Amino-l H-pyrazole gebildet. 

The reactions studied are Addition of ammonia to 1,2,4-triazines and oxidation of the amino-dihydro compounds with potassium permanganate to amino-1,2,4-triazines (Scheme 15) addition of Grignard reagents or other carbanions to 1,2,4-triazines and oxidation of the dihydro adducts with potassium permanganate or potassium hexacyanoferrate(III) (Scheme 17) and addition of... 

N-l, N-2- and 7V-4-substituted amidrazones (358)-(360) can be used for the synthesis of 1-, 2-, or 4-substituted dihydro-1,2,4-triazines <82CB2807>. Reactions of 1,2-dicarbonyl compounds with hydrazidines (361) have been used for the synthesis of 4-amino-dihydro-1,2,4-triazines <85LA78>. The examples shown (Scheme 67), employing the cyclopentanedione (362), result in a variety of reduced cyclopenta[c]-l, 2,4-triazines. 

Imines are reduced by triethylsilane to their amines when the proper Ir orNi catalysts areemployed. Non-metal-mediated reductions of C=N groups by EtsSiH are also possible. Among these, the trifluorosulfonic acid promoted reductive amidation of aliphatic and aromatic aldehydes with EtsSiH is an excellent way to mono (V-alkylate aliphatic and aromatic amides, thioamides, carbamates, and ureas (eq 26). It is also worth noting that trifluorosulfonic acid/EtsSiH reduces acyl- and tosylhydrazones to hydrazines and 2-aminopyrimidines to 2-amino-dihydro-or 2-aminotetrahydropyrimidines (eq 27). ... 

CsrHasNsOa 8 p>An]Bolazo-5 -amino-dihydro chinin 25 II423. 

C13H17N3O3S, 3-Dimethylamino-4,4-dimethyl-5,6-dihydro-4H-1,2,5-ben-zothiadiazocin-6-one-1,1-dioxide, 43B, 483 C13H18N2O2S, 2-(N-2,6-Dimethylphenyl-N-mesyl-amino)-dihydro-1,3-thiazine, 43B, 484... 

Chemiluminescent Immunoassay. Chemiluminescence is the emission of visible light resulting from a chemical reaction. The majority of such reactions are oxidations, using oxygen or peroxides, and among the first chemicals studied for chemiluminescence were luminol (5-amino-2,3-dihydro-l,4-phthalazinedione [521-31-3]) and its derivatives (see Luminescent materials, chemiluminescence). Luminol or isoluminol can be directly linked to antibodies and used in a system with peroxidase to detect specific antigens. One of the first appHcations of this approach was for the detection of biotin (31). 

Tc(III)(l, 2-bis((dihydro-2,2, 5,5-tetramethyl3(2i/)-furanonato)methylene)amino)ethane)(TMPP)2 ( Tc-furifosrnin), where... 

L-Fohc acid (1) contains three subunits 6-methylpterin, -aminobenzoic acid, and L-glutamic acid. The Chemicaly hstracts name is A/- [4- [ (2-amino-l,4-dihydro-4-oxo-6-pteridinyl)methyl amin o]benzoy1]-T-glutamic acid. 

Pyrimido[4,5- f]pyrimidines may be used as pyrimidine precursors. Thus, the dihydro derivative (736) undergoes alkaline hydrolysis to the amide (737 R = PrCO) which may be deacylated in ethanolic hydrogen chloride to give 5-aminomethyl-2-propylpyrimidin-4-amine (737 R = H) (64CPB393) rather similarly, the pyrimidopyrimidinedione (738) reacts with amines to give, for example, 6-amino-5-benzyliminomethyl-l,3-dimethylpyrimidine-2,4(lFf,3Ff)-dione (739 R = CH2Ph) or the hydrazone (739 R = NH2) (74JCS(Pl)1812). 

Other pyrimidine starting materials include 5-amino-6-methyl derivatives, which with oxalates give 6,7-dihydroxypyrido[3,2-acid derivatives, which with malononitrile are converted into 5,6-dihydro-7-aminopyrido[2,3-[Pg.227]

Of the classical Hofmann, Curtius, Lossen and Schmidt degradations, only a rare example of the first is known, hypobromite converting 4,7-diamino-2-phenyl-6-pteridinecar-boxamide (208) into 8-amino-2,3-dihydro-6-phenyl-l//-imidazo[4,5-g]pteridin-2-one (209 equation 64) (63JOC1203). 

An unusual approach to the lumazine nucleus was found in the photochemical transformation of 6-azido-l,3-dimethyluracil (289) with various amino compounds (78JA7661). Irradiation of (289) in the presence of ethyl a-amino acid esters forms 7-substituted 7,8-dihydrolumazin-6-ones (288), and with a-aminoketones 6-substituted 7,8-dihydro-lumazines (290) are formed (equation 103). 

The l,3-dihydro-2,l-benzisoxazole-3-carboxyIic acid was prepared by either base treatment of N-hydroxyisatin or the rearrangement of N-hydroxyisatin monooxime with dilute acid (67AHC(8)277). The addition of amines to 3-unsubstituted-2,l-benzisoxazolium salts gave 3-amino-l,3-dihydro-2,l-benzisoxazoles (72CPB2209). 

When saccharin is treated with diethyl phosphorothiolothionate, the 3-ethylmercapto compound is obtained, rather than the expected organophosphorus compound (77 ACS(B)460). Treatment of saccharin with phosphorus pentoxide and amines gives 3-(substituted-amino)-1,2-benzisothiazole 1,1-dioxides, via an intermediate phosphate (81ZN(B)1640). Reduction of saccharin with zinc and hydrochloric acid gives 2,3-dihydro-l,2-benzisothiazole 1,1-dioxide, the method being used to estimate saccharin in foodstuffs (75MI41701). 

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