Triethyl orthoacetate

Chloro-1 -methyl-5-phenyl-s-trizolo[4,3-a]quinoline A stirred mixture of 6short,glass helix-packed column. The mixture was concentrated to dryness In vacuo and the residue was crystallized from methanol-ethyl acetate to give 1.28 g of 7-chloro-1-methyl-5-phenyl-s-triazolo[4,3-a]-quinoline (83.9% yield). The analytical sample was crystallized from methylene chloride methanol and had a melting point 252.5°-253.5°C. 

Johnson s classic synthesis of progesterone (1) commences with the reaction of 2-methacrolein (22) with the Grignard reagent derived from l-bromo-3-pentyne to give ally lie alcohol 20 (see Scheme 3a). It is inconsequential that 20 is produced in racemic form because treatment of 20 with triethyl orthoacetate and a catalytic amount of propionic acid at 138 °C furnishes 18 in an overall yield of 55 % through a process that sacrifices the stereogenic center created in the carbonyl addition reaction. In the presence of propionic acid, allylic alcohol 20 and triethyl orthoacetate combine to give... 

In some cases we may benefit from adopting a semi-continuous mode of operation, e.g. to a batch of one reactant we continuously feed the other reactant, while removing a volatile product continuously. An example where this is advantageous is the production of ethyl-4-pentenoate, CH2=(CH2)3(CO)OEt from allyl alcohol and triethyl orthoacetate, CHs-CfOEt). Continuous addition of allyl alcohol to a batch of triethyl orthoacetate and continuous removal of the produced ethylalcohol (and. some allyl alcohol) by distillation resulted in high yields of the dersired ester ethyl-4-pentenoate. By contrast, if allyl alcohol and triethyl orthoacetate were reacted in a batch-wise manner the product consisted of a 1 1 mixture of the desired ester and the undesired ester (Anderson, 2000, p 279 Bollyn and Wright, 1998). 

Scheme 6.15 gives some representative examples of the orthoester Claisen rearrangement. Entry 1 is an example of the standard conditions for the orthoester Claisen rearrangement using triethyl orthoacetate as the reactant. The allylic alcohol is heated in an excess of the orthoester (5.75 equivalents) with 5 mol % of propanoic acid. Ethanol is distilled from the reaction mixture. The E-double bond arises from the chair TS. 

The diaminomaleonitrile derivative 186 is transformed into 187 by treatment with triethyl orthoacetate (Equation 27) <2006S3437>. Other orthoesters react similarly. 

Diazoxide 7-chloro-3-methyl-2-//-l,2,4-benzothiadiazin-l,1-dioxide (21.3.14), is synthesized by condensating 2-aminosulfonyl-4-chloroaniline with triethyl orthoacetate [34-36]. 

Ethyl S,4-deaadienoate (1). A 300-mL, round-bottomed flask equipped with a reflux condenser is charged with 12.1 g (0.096 mol) of l-octyn-3-ol (Note 1), 100 g (0.616 mol) of triethyl orthoacetate (Note 2), and 0.24 g (3.2 mmol) of propionic acid. The solution is heated at 140-150°C in an oil bath. Every 2 hr, the ethanol produced is removed under reduced pressure with a rotary evaporator, and then 10 g (0.062 mol) of triethyl orthoacetate and 0.024 g (0.32 mmol) of propionic acid are added. The mixture is heated until the starting material is consumed (6-8 hr) (Note 3). Excess triethyl orthoacetate is removed under reduced pressure (Note 4). The residue is distilled under reduced pressure to give 15.4-17.2 g (82-91t) of 1 (Note 5) as a clean oil, bp 80-85°C (0.3 mm). 

The product might contain trace amounts of triethyl orthoacetate,... 

Triethyl orthoacetate Orthoacetic acid, triethyl ester (8) Ethane, 1,1,1-triethoxy- (9) (78-39-7)... 

Triethyl orthoacetate was used as supplied by Aldrich Chemical... 

The checkers removed excess triethyl orthoacetate under reduced... 

Compounds such as 304, when treated with triethyl orthoacetate, produce the ethoxyethylideneamino derivative 307 (Equation 111), which can also serve to generate furo[2,3-,7 pyrimidines such as 308 when allowed to react with cold hydrazine <1995MI177, 1998IJH147>. Treatment of 307b with phenylhydrazine affords the W-phenyl analog of 308b (65%) <1995MI177>. 

Kislyi et al. facilitated the formation of [l,2,3]triazolo[4,5-r lpyrimidin-7-ones from 5-amino-l,2,3-triazole-4-carbox-amides under Vilsmeier conditions (Scheme 47) or using triethyl orthoacetate and acetic anhydride (Scheme 48) <2003RCB1770>. These methods could be used to isolate the respective 5-formamidine 69 and 5-imidoate 70 reaction intermediates, if lower temperatures and shorter reaction times were employed. 

Ethoxyacetylene reacts with refluxing ethanolic sodium ethoxide to give a 44% yield of triethyl orthoacetate [128], In addition, aldoximes and ketoximes react with ethoxyacetylene to give orthoacetic acid derivatives shown in Eqs. (35) and (36) [129]. More work is required to establish the generality of this reaction. 

Preparation of triethyl orthoacetate by the reaction of ethyl 1,1-diazido-ethyl ether with sodium ethoxide [207]. 

Triethyl orthoacetate was used as supplied by Aldrich Chemical Company, inc. (97% purity) or by Tokyo Kasei Kogyo Co., Ltd. (98% purity). 

The checkers removed the ethanol with a rotary evaporator and replaced it with fresh triethyl orthoacetate (10 g) and propionic acid (0.024 g) after 2, 4, and 6 hr. 

The checkers removed excess triethyl orthoacetate under reduced pressure (0.05 mm) overnight. The recovered material may be easily purified by distillation and reused. 

The Matheson, Coleman and Bell product was used without purification. After a 10-ml. forerun, the triethyl orthoacetate was distilled (b.p. 142—147°) directly into the reaction flash. 

A. 3-Phenyl-4-pentenoic acid. A mixture of 33.7 g (0.25 mol) of cinnamyl alcohol (Note 1), 46.1 mL (0.25 mol] of triethyl orthoacetate (Note 1), and 0.19 mL (1.5 mmol) of hexanoic acid (Note 2) is placed in a 250-mL, round-bottomed flask equipped with a thermometer, Claisen head, and condenser. The solution is heated in an oil hath with distillation of ethanol. After 3 hr, distillation of ethanol slows and another 0.1-mL portion of hexanoic acid is added. Additional portions (0.1 mL) of the catalyst are added again at 3.5 and 4.5 hr. After 6 hr, a total of 27 mL of ethanol, out of a theoretical 29.2 mL, has been collected, and GC analysis (Note 3)... 

Triethyl orthoacetate Orthoacetic acid, triethyl ester (8) ... 

The method has been applied by the submitters2 to the preparation of cyclohexylmethylpropiolaldehyde diethyl acetal (54% yield) from cyclohexylmethylacetylene and triethyl orthoformate of phenylethynyl n-butyl dimethyl ketal (40% yield) from phenylacetylene and trimethyl -orthovalerate and of phenylethynyl methyl diethyl ketal (34% yield) from phenylacetylene and triethyl orthoacetate. w-B utylpropiolaldehyde diethyl acetal was isolated in 32% yield by heating an equimolar mixture of 1-hexyne and triethyl orthoformate containing catalytic amounts of a zinc chloride-zinc iodide catalyst under autogenous pressure at 190° for 3 hours. 

Epoxidation. Reaction of ortho esters with 90% H,0, generates a species that can epoxidize alkenes. Of several ortho esters tested, triethyl orthoacetate was most satisfactory. An example is shown in equation (l).1... 

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