5-Amino-2-ethoxycarbonyl

Amino- -(ethoxycarbonyl-methyl-atnid) XV/1, 99, 283 -(1, l-dimethyl-2 nitro-ethylamid) E5, 1040... 

With the dicyclohexylcarbodiimide (DCQ reagent racemization is more pronounced in polar solvents such as DMF than in CHjCl2, for example. An efficient method for reduction of racemization in coupling with DCC is to use additives such as N-hydroxysuccinimide or l-hydroxybenzotriazole. A possible explanation for this effect of nucleophilic additives is that they compete with the amino component for the acyl group to form active esters, which in turn reaa without racemization. There are some other condensation agents (e.g. 2-ethyl-7-hydroxybenz[d]isoxazolium and l-ethoxycarbonyl-2-ethoxy-l,2-dihydroquinoline) that have been found not to lead to significant racemization. They have, however, not been widely tested in peptide synthesis. 

The high reactivity of the exocyclic 4-NH- group is again illustrated by the reaction of 2-imino-3-phenyl-4-amino-5-(ethoxycarbonyl)-4-thiazoline with EtOjCCH SCN, which yields 134 (296), and by the intramolecular preparation of the dihydrothiazolo[4,5-h]pyridine derivative 136 (297) (Scheme 89). 

The problem is more complicated when the ambident nucleophile. 2-aminothiazole, reacts with an ambident electrophilic center. Such an example is provided by the reaction between 2-amino-5-R-thiazole and ethoxycarbonyl isothiocyanate (144), which has been thoroughly studied by Nagano et al. (64, 78, 264) the various possibilities are summarized in Scheme 95. At 5°C, in ethyl acetate, the only observed products were 145a, 148. and 150. Product 148 must be heated to 180°C for 5 hr to give in low yield (25%) the thiazolo[3.2-a]-s-tnazine-2-thio-4-one (148a) (102). This establishes that attack 1-B is probably not possible at -5°C. When R = H the percentages of 145a. 148. and 150 are 29, 50, and 7%, respectively. These results show that ... 

The ambident reactivity of 2-amino-4,5-disubstituted thiazoles toward benzoylthiocyanate 153 has been studied (311) and parallels that of ethoxycarbonyl isothiocyanate (Scheme 98) the percentages of 154. 155. 

Aziridine, alkylidene-N-ethoxycarbonyl thermolysis, 7, 78 Aziridine, /V-amino-... 

Thiazole, 5-amino-4-ethoxycarbonyl-2-methyl-synthesis, 6, 306 Thiazole, 2-amino-4-(2 -furyl)-bromination, 6, 256 Thiazole, 2-amino-4-hydroxy-synthesis, 6, 296 Thiazole, 5-amino-2-hydroxy-synthesis, 6, 301 Thiazole, 5-amino-2-mercapto-synthesis, 6, 301 Thiazole, 2-amino-4-methyl-alkylation, 6, 256 synthesis, 6, 300 Thiazole, 2-amino-5-nitro-antiparasitic activity, 1, 180... 

Thieno[2,3-c]pyridine, 2-amino-6-benzyl-3-ethoxycarbonyl-4,5,6,7-tetrahydro-biological activity, 4, 1015 Thieno[2,3-c]pyridine, 4,5,6,7-tetrahydro-biological activity, 4, 1015 Thieno[3,2-6]pyridine, 3-hydroxy-synthesis, 4, 1010... 

Thiophene, 2-amino-3-cyano-5-phenyl-synthesis, 4, 888-889 Thiophene, 3-amino-4,5-dihydro-cycloaddition reactions, 4, 848 Thiophene, 2-amino-3-ethoxycarbonyl-ring opening, 4, 73 Thiophene, 2-amino-5-methyl-synthesis, 4, 73 Thiophene, 2-anilino-synthesis, 4, 923-924 Thiophene, aryl-synthesis, 4, 836, 914-916 Thiophene, 2-(arylamino)-3-nitro-synthesis, 4, 892 Thiophene, azido-nitrenes, 4, 818-820 reactions, 4, 818-820 thermal fragmentation, 4, 819-820 Thiophene, 3-azido-4-formyl-reactions... 

From amino- and alkoxybutenones and benzonitrile iV-oxide as well as from acetyl- and ethoxycarbonyl-iV-phenylnitrilamines and p-methoxyphenyl azide, the corresponding functional isoxazoles, pyrazoles, and tiiazoles were obtained (83DIS 83ZOR2281 92SC2902). 

Cyclization of methyl 2-[2-benzoyl-2-ethoxycarbonyl-l-vinyl)amino]-3-[(4-methyl-2-pyridyl)amino]acrylate (311) afforded the 3-amino-8-methyl-4//-pyrido[l,2-n]pyrimidin-4-one derivative 312 (97JHC1511). 

An ANRORC mechanism has also been proposed (besides an inverse cycloaddition reaction) in the conversion of 1-methylpyrimidinium iodide into 3-ethoxycarbonyl-2-methylpyridine on treatment with ethyl -amino-crotonate (95RCB1272) (Scheme 23a). The reaction starts by addition of the -carbon of the crotonate at the electron-deficient 4-position of the... 

IB) 1-(2-Amino-5-chlorophenyl)-1-(2-fluorophenyl)-3,3-bis-(ethoxycarbonyl)-2-a2a-prop-1-ene A mixture of 88 g of the product obtained above, 300 g of ethyl aminomalonate hydrochloride and 60 ml of acetic acid in 2.3 liters of absolute ethanol is heated to the reflux temperature for 6 hours. The alcohol and the acetic acid are evaporated in vacuo and the residue is taken up in ether. The solution is washed with a dilute sodium bicarbonate solution and... 

The starting material may be produced by reacting 6-amino-2-methylthiopyrimidine with ethoxymethylene malonic acid diethyl ester. The intermediate thus produced is converted by boiling in diphenyl ether to 6-ethoxycarbonyl-2-methylthio-5-oxo-5,B-dihydropyrido-[2,3-d]pyrimidine. That is hydrolyzed by sodium hydroxide to cleave the ethoxy group and then ethylated with diethyl sulfate to give the starting material. 

A solution of 1-benzyl-4-piperidone, ethyl cyanoacetate, powdery sulfur and morpholine in ethanol is heated moderately under reflux for about 20 minutes to dissolve the powdery sulfur. The mixture is heated under reflux for one further hour to complete the reaction. On standing at room temperature, the mixture yields a precipitate. The precipitate is collected by filtration, washed well with methanol and recrystallized from methanol to give 2-amino-6-benzyl-3-ethoxycarbonyl-4,5,6,7-tetrahydrothieno(2,3-c)-pyridine as almost colorless needles melting at 112° to 113°C. 

In contrast to the above rearrangement reaction, the analogs 1 rearrange to 5-[(ethoxycarbonyl)-amino]-2-phenylpyridines 2 under thermal conditions.29 30... 

Ethoxycarbonyl)amino]benzaldehyde oxime (2.1 g, 10 mmol) was stirred with 2M NaOH (25 mL, 50 mmol) and the mixture was heated on a steam bath until a clear solution had formed. The hot solution was made weakly acid and cooled, whereupon the product crystallized as the dihydrate mp 244 C (dec.). 

Chloro-3- [(1 -ethoxycarbonyl-1 -methylethyl)amino] -4-nitrobenzene (61) gave 6-cbloro-3,3-dimetbyl-3,4-dibydro-2(lF/)-quinoxalinone (62) (TiCl3, AcONa,... 

CN [25-[2a,5a,6P(S )]]-6-[(aminophenylacetyl)amino]-3,3-dimethyl-7-oxo-4-thia-l-azabicyclo[3.2.0]heptane-2-carboxylic acid l-[(ethoxycarbonyl)oxy]ethyl ester... 

CN fl5-IIa,9a(R )]]-9-[[l-(ethoxycarbonyl)-3-phenyIpropyl]amino]octahydro-IO OXO-6//-pyridazino[l,2-a][ 1,2]diazepine- 1-carboxylic acid... 

S-[l[/ (R )],2a,3a(i,6ap]]-l-[2-[[l-(ethoxycarbonyl)-3-phenylpropyl]amino]-l-oxopropyl]octahydrocyclopenta[6]pyrrole-2-carboxylic acid... 

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