Tetrahydrofuran → 4-(7-Chloro-quinazolin-4-yl)-piperidine-1,4-dicarboxylic acid 1-tert-butyl ester 4-methyl ester

To a stirred mixture of 4,7-Dichloroquinazoline (800 mg, 4 mmol) and piperidine-1,4-dicarboxylic acid 1-tert-butyl ester 4-methyl ester (1.2 g, 5.2 mmol), as prepared in Example 1a, in a sealed vial at rt was added drop-wise a 1 M solution of LiHMDS in THF (6 mL, 6 mmol). The mixture was stirred at rt overnight. It was then quenched with aqueous NaH2PO4 and the mixture was extracted with DCM. The DCM layer was drawn off, washed with water, brine, dried over anhydrous MgSO4, filtered and concentrated in vacuo to obtain 2.2 g (>100%) of crude 4-(7-chloro-quinazolin-4-yl)-piperidine-1,4-dicarboxylic acid 1-tert-butyl ester 4-methyl ester (3a) as a yellow semi-solid which was used as such for the next step. Solid KOH (224 mg, 4 mmol) was added to a suspension of 4-(7-chloro-quinazolin-4-yl)-piperidine-1,4-dicarboxylic acid 1-tert-butyl ester 4-methyl ester (3a; 41 mg, 0. 1 mmol) in a 1:1 mixture of dioxane and water (1 mL). The mixture was stirred at 100° C. for 3 h. It was then cooled to rt and concentrated in vacuo. The residue was dissolved in DCM and washed with water, brine, dried over anhydrous MgSO4, filtered and concentrated in vacuo to obtain crude 4-(7-chloro-quinazolin-4-yl)-piperidine-1-carboxylic acid tert-butyl ester (3b). This was dissolved in 2 mL of 3M HCl/MeOH was stirred at rt for 1 h and then concentrated in vacuo to obtain crude 4-(7-chloro-quinazolin-4-yl)-piperidine (3c) as a di-HCl salt.

1. customas prepared in Example 1a
2. customIt was then quenched with aqueous NaH2PO4
3. extractionthe mixture was extracted with DCM
4. washwashed with water, brine
5. dry with materialdried over anhydrous MgSO4
6. filtrationfiltered
7. concentrationconcentrated in vacuo

ORD record

ord-3b7e875d8a72493d9a5028668ddc78a2

Source dataset

uspto-grants-2010_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07825244B2