Malonate, chloro, reaction with

The addition of nucleophiles to cyclic fluoroolefins has been reviewed by Park et al. [2 ]. The reaction with alcohols proceeds by addition-elimination to yield the cyclic vinylic ether, as illustrated by tlie reaction of l,2-dichloro-3,3-di-fluorocyclopropene Further reaction results in cyclopropane ring opening at the bond opposite the difluoromethylene carbon to give preferentially the methyl and ortho esters of (Z)-3-chloro-2-fluoroacrylic acid and a small amount of dimethyl malonate [29] (equation 8). 

The same methodology was also used starting from the ethyl 6-amino-7-chloro-l-ethyl-4-oxo-l,4-dihydroquinoline-3-carboxylate, prepared by reduction of the nitro derivative. The requisite nitro derivative was prepared by nitration of ethyl 7-chloro-l-ethyl-4-oxo-l,4-dihydroquinoline-3-carboxylate. A second isomer was prepared from 4-chloro-3-nitroaniline by reaction with diethyl ethoxymethylene-malonate, subsequent thermal cyclization, and further ethylation because of low solubility of the formed quinolone. After separation and reduction, the ethyl 7-amino-6-chloro-l-ethyl-4-oxo-l,4-dihydroquinoline-3-carboxylate 32 was obtained. The ort/io-chloroaminoquinolones 32,33 were cyclized to the corresponding 2-substituted thiazoloquinolines 34 and 35, and the latter were derivatized (Scheme 19) (74JAP(K)4, 79CPB1). 

The synthesis of the corresponding naphthyridone scaffold was carried out according to the methods reported by Chu et al. [12] and Sanchez et al. [13]. Namely, the hydrolysis of ethyl 2,6-dichloro-5-fluoronicotinate (3) [14] followed by reaction with thionyl chloride results in the formation of 2,6-dichloro-5-fluoronicotinyl chloride (4). Treatment of this compound with monoethyl malonate in THF under n-butyllithium followed by acidification and decarboxylation gives rise to ethyl 2,6-dichloro-5-fluoronicotinylacetate (5). Reaction of compound 5 with ethyl orthoformate in acetic acid followed by cyclopropylamine results in the formation of 3-cyclopropylamino-2-(2,6-dichloro-5-fluoronicotinyl)acrylate (6), the cyclization reaction of which under NaH/THF gives rise to the required ethyl l-cyclopropyl-6-fluoro-7-chloro-l,4-dihydro-4-oxo-l,8-naphthyridine-3-carboxylate (7), as shown in Scheme 3. 

In contrast with the reaction of the chloropyridine, but in keeping with its observed reactions with diethyl malonate under classical procedures, 3-chloro-l,2-benzoisothiazole produces not only the SNAr products, (1) and (2) (Scheme 2.3), but also products arising under the basic conditions from ring opening of the isothiazole... 

Chorazepate Chorazepate, 7-chloro-2,3-dihydro-2,2-dihydroxy-5-phenyl-1H-1,4-benzo-diazepin-3-carboxylic acid (5.1.34), which is used in the form of a dipotassium salt, is synthesized by yet another interesting synthetic scheme. 2-Amino-5-chlorobenzonitrile is used as the initial compound, which upon reaction with phenyhnagnesiumbromide is transformed into 2-amino-5-chlorbenzophenone imine (5.1.32). Reacting this with amino-malonic ester gives a heterocyclization product, 7-chloro-l,3-dihydro-3-carbethoxy-5-phenyl-2H-benzodiazepin-2-one (5.1.33), which upon hydrolysis using an alcoholic solution of potassium hydroxide forms a dipotassium salt (5.1.34), chlorazepate [30-32]. 

Azodicarboxylates 4 have been used in the electrophilic reaction with diethyl malonate since 1924 [3] however only recently were these reagents recognized as particularly useful for the introduction of an amino moiety after hydrogenolysis of the hydrazide adduct [3], More recently, chloro nitroso reagents of type 5 have been introduced by Oppolzer [4]. These reagents are particularly reactive, giving... 

Several approaches to the synthesis of morphinans start with cyclohexanone intermediates leading to octahydroisoquinolines such as 3 by way of a route similar to that exploited by Grewe (Scheme 3.1). Amination of 2-hydroxymethylenecyclohexanone (6) followed by reaction with malonic ester afforded the hexahydroisoquinoline, 7, that was decarboxylated and converted on a commercial scale to 5,6,7,8-tetrahydroisoquinoline(9) via the 3-chloro intermediate. 

Chloro-benzo-l Athia-2,4-diazine 161 (R = CF3) affords 1-amino adducts 162 upon reaction with piperidine and cyclohexylamine (Scheme 12) <2002UKZ44>, while treatment of 161 (R = CCl3, CF3, Ph) with malonate-type nucleophiles produces ylides represented as 163 (X = C02R, CN) (Scheme 12) <2002UKZ80>. 

It is possible to prepare 1-acetoxy-4-chloro-2-alkenes from conjugated dienes with high selectivity. In the presence of stoichiometric amounts of LiOAc and LiCl, l-acetoxy-4-chloro-2-hutene (358) is obtained from butadiene[307], and cw-l-acetoxy-4-chloro-2-cyclohexene (360) is obtained from 1.3-cyclohexa-diene with 99% selectivity[308]. Neither the 1.4-dichloride nor 1.4-diacetate is formed. Good stereocontrol is also observed with acyclic diene.s[309]. The chloride and acetoxy groups have different reactivities. The Pd-catalyzed selective displacement of the chloride in 358 with diethylamine gives 359 without attacking allylic acetate, and the chloride in 360 is displaced with malonate with retention of the stereochemistry to give 361, while the uncatalyzed reaction affords the inversion product 362. 

Chloro-l,2,3-thiadiazole-4-carboxamides 38 react with the sodium salt of diethyl malonate to give the corresponding malonic acid derivatives 39. The yield in these reactions falls as the electron-releasing properties of the 4-substituents in the aromatic ring increase (Equation 8) <1997JCM396>. 

There are very few precedents for the reaction of cyclic a-halo ethers with carbanions. Zelinski and coworkers114 and Schudel and Rice115 reported the preparation of diethyl DL-tetrahydropyran-2-ylmalonate (137) by treatment of 2-bromo- or 2-chloro-tetrahydropyran (136) with diethyl sodiomalonate. The product was subsequently converted into the malonic and acetic acid derivatives, 138 and 139, respectively. The same sequence has also been reported by other workers.116... 

Guo et al. prepared N-(3-chloro-4-fluorophenyl)aminomethylenemalo-nate (256, R = 3-C1, R1 = 4-F, R2 = R3 = Et) in 60-70% yields when 3-chloro-4-fluoroaniline was reacted with triethyl orthoformate and diethyl malonate in the presence of a Lewis acid. From the reaction mixture, ethyl A-(3-chloro-4-fluorophenyl)-2-[(3-chloro-4-fluorophenyl)-aminomethylene]malonamate and A-(3-chloro-4-fluorophenyl)formanilide were also isolated as byproducts (88MI3). 

The reaction of tetrahydro-l,3-thiazine-2-thione and diethyl 2-chloro-malonate in the presence of triethylamine in boiling methylene chloride for 1.5 hr gave tetrahydro-1,3-thiazin-2-ylidenemalonate (508) in 33% yield via 507 through Eschenmoser sulfur elimination, together with traces of the mesoionic derivative (509) [77JCS(P 1) 1107]. In a similar reaction, diethyl 2-bromomalonate afforded the mesoionic compound (509) in 80% yield. Tetrahydro-l,3-thiazin-2-ylidenemalonate (508) was also obtained in 42% yield from 509 by irradiation in the presence of tributylphosphine in ethanol for 15 hr under argon [77JCS(P1)1107]. 

Reaction of 3-chloro-1,2-benzoisothiazole with diethyl malonate... 

---