Some formylation reactions of imidazo[1,5‐<i>a</i>] pyridine and pyrrocoline

Fuentes, Omar; Paudler, William W.

doi:10.1002/jhet.5570120235

Cited by 31 publications

(11 citation statements)

References 5 publications

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“…Scheme 38 Electrophilic Substitutions on Imidazo[1,5-a]pyridines [150,157±159] [159] To an ice water cooled soln of imidazo[1,5-a]pyridine (0.59 g, 0.005 mol) in DMF (0.4 g, 0.0055 mol) was added dropwise, with stirring, POCl 3 (1.07 g, 0.007 mol). After 1 h of heating on a steam bath, the mixture was poured into ice water, made basic with concd NH 4 OH, and extracted with CHCl 3 (3 200 mL).…”

Section: Methods 1: Electrophilic Substitutionmentioning

confidence: 99%

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Product Class 5: Azaindolizines with Two Nitrogen Atoms in the Five-Membered Ring

Neier¹,

Bellus²

2002

Category 2, Hetarenes and Related Ring Systems

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In contrast to Section 12.5.1.1.1.1, where in most cases the first reaction step is the quaternization of a pyridin-2-amine derivative followed by nucleophilic attack of the 2-amino group on an appropriate functional group to form the imidazole ring, several ring closures have been elaborated starting from substituted pyridin-2-amines. In these cases, the â-carbon atom of the carbon chain attached to the 2-amino group bears an appropriate functional group, and a nucleophilic attack of the pyridine ring nitrogen atom at this center results in formation of the imidazole ring. Such syntheses are shown in Scheme 8.

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Section: Methods 1: Electrophilic Substitutionmentioning

confidence: 99%

“…[159] The 5-methyl derivative 215 reacts likewise to give 216. [159] The 5-methyl derivative 215 reacts likewise to give 216.…”

Section: Methods 2: Substitution Via Lithiationmentioning

confidence: 99%

Product Class 5: Azaindolizines with Two Nitrogen Atoms in the Five-Membered Ring

Neier¹,

Bellus²

2002

Category 2, Hetarenes and Related Ring Systems

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“…The cyclization of N1-(2-pyridylmethyl)-substituted benzamides (3a-h) in phosphorous oxychloride gave the intermediates substituted phenyl imidazo[1,5-a]pyridines (4a-h) in good yield. Formylation of substituted phenyl imidazo [1,5-a]pyridines (4a-h) in DMF and phosphorous oxychloride gave 3-(substituted phenyl)imidazo[1,5-a]pyridine-1-carbaldehyde (5a-h) [18].…”

Section: Chemistrymentioning

confidence: 99%

Synthesis and anticancer activity of oxindole derived imidazo[1,5-a]pyrazines

Kamal

Ramakrishna

Raju

et al. 2011

European Journal of Medicinal Chemistry

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“…The imidazopyridine 19 was prepared as shown in Charts 1 and 2. 1-Formylimidazo[1,5-a]pyridine 10) was treated with Wittig reagent to give the b,gunsaturated acid 5. Esterification and catalytic reduction of 5 afforded 7, which was derived to 19 in a manner similar to 17.…”

Section: The Discovery Of An Excellent Nonsteroidal Compound Fk143 mentioning

confidence: 99%

“…After 20 min, 1-formylimidazo[1,5-a]pyridine 10) (2.46 g, 16.8 mmol) was added, and the mixture was stirred at 30°C for 1 h. The reaction was quenched by the addition of ice and the mixture was made acidic by 1 N HCl and extracted with EtOAc. The extract was washed with brine, dried over Na 2 SO 4 and evaporated in vacuo.…”

Section: Trans-4-(imidazo[15-a]pyridin-1-yl)-3-butenoic Acid (5)mentioning

confidence: 99%

4-(Benzoylindolizinyl)butyric Acids; Novel Nonsteroidal Inhibitors of Steroid 5.ALPHA.-Reductase. III.

et al. 2001

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Benign prostatic hyperplasia (BPH) is a common disorder in aging males. Approximately 50% to 75% of all males over the age of 50 are known to develop this condition.3) This disorder is characterized by a progressive enlargement of the prostate grand, leading to an increase in pressure on the urethra; it results in obstruction of urinary flow. In light of the high incidence of this condition, it is obvious that some form of chemical therapy would be of immense potential importance in treating BPH. 4)Steroid 5a-reductase enzymatically converts testosterone (T) into 5a-dihydrotestosterone (DHT), which is the most active agonist for androgen receptors.5) An accumulation of DHT to high levels in the prostate gland or the skin is recognized as leading to various pathological conditions such as BPH, acne, female hirsutism, and male pattern baldness. 4)Therefore, therapy with a 5a-reductase inhibitor would be expected to lead to a decrease in DHT concentration within the prostate gland or other tissues, and may be an extremely useful agent for the treatment of BPH and other diseases.Though many laboratories have investigated 5a-reductase inhibitors, 6,7) these efforts have predominantly concentrated on compounds with a steroidal structure, for example finasteride 6a) (Table 1). However, due to the presence of a steroidal structure, there is the strong possibility of unwanted side-effects. 8) We previously reported 1) the discovery of an excellent nonsteroidal compound, FK143,methyl]amino]benzoyl]-1H-indol-1-yl]butyric acid (Table 1), which displays high in vitro inhibitory activity against human prostatic 5a-reductase (IC 50 ϭ1.9 nM) and in vivo inhibitory activity against the castrated young rat model. 9) In this model, the growth of ventral prostate was induced by the subcutaneous injection of testosterone propionate (TP) to castrated young rats and was reduced by administration of the inhibitor. In order to obtain a more clinically effective candidate, we have now investigated more active compounds against this in vivo model. We employed two types of modification, 1) altering the indole ring to other hetrocyclic rings, and 2) changing the benzoyl substituent at the 3-position.Chemistry The indolizine derivative 17 was prepared as shown in Charts 1 and 2. Friedel-Crafts acylation of indolizine was carried out with ethyl 3-(chloroformyl)propionate and aluminum chloride to obtain 1 and 2. The ketone 1 was reduced to 3 by a borane-tetrahydrofuran (THF) complex, and 3 was acylated with 3-nitrobenzoyl chloride to obtain 8. The catalytic reduction of 8 gave the amine 11, which was alkylated with bis(4-isobutylphenyl)chloromethane to afford 14. 17 was obtained by hydrolysis of the ester 14. The indolizine derivative 18 was prepared from 2 in a similar manner to 17 (Charts 1, 2). The imidazopyridine 19 was prepared as shown in Charts 1 and 2. 1-Formylimidazo[1,5-a]pyridine 10) was treated with Wittig reagent to give the b,gunsaturated acid 5. Esterification and catalytic reduction of 5 afforded 7, which was derived to 19 in a...

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Some formylation reactions of imidazo[1,5‐a] pyridine and pyrrocoline

Cited by 31 publications

References 5 publications

Product Class 5: Azaindolizines with Two Nitrogen Atoms in the Five-Membered Ring

Product Class 5: Azaindolizines with Two Nitrogen Atoms in the Five-Membered Ring

Synthesis and anticancer activity of oxindole derived imidazo[1,5-a]pyrazines

4-(Benzoylindolizinyl)butyric Acids; Novel Nonsteroidal Inhibitors of Steroid 5.ALPHA.-Reductase. III.

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