Pentanoic acid, 5-amino-, ethyl ester, hydrochloride (1:1)

Step i. DMF (30 mL) and ethyl-5-bromovalerate (S4) (1.5 mL, 9.48 mmol) were added to NaN3 (1.880 g, 28.92 mmol) maintained under N2. The ensuing mixture was magnetically stirred for 18 then H2O (30 mL) was added. The aqueous phase was extracted with Et2O (4x 30 mL) and the organic extracts were combined and successively washed with H2O (3x 20 mL) and brine (2x 30 mL). The organic extracts were then dried (MgSO4), filtered, and concentrated under reduced pressure to provide a pale-yellow crude residue containing compound S5 (1.90 g). Compound S5 was not purified, but immediately subject to the reaction outlined below. Step ii. HCl (1.6 mL of a 10 M aqueous solution) and 5% Pd/C (250 mg, 0.12 mmol, 1.2%) were added toa solution of compound S5 in EtOH (60 mL). The ensuing mixture was reacted under H2 in a Parr shaker hydrogenator (33 psi). After 1 h, the mixture was filtered through as plug of Celite then concentrated under reduced pressure to provide a compound S6 (2.63 g) as a colourless solid. Compound S6 was not purified, but immediately subject to the reaction outlined below. Step iii. Glacial acetic acid (380 muL, 6.66 mmol) was added to a magnetically stirred solution of 2, 5-dimethoxytetrahydrofuran (1.70 mL, 13.1 mmol) in H2O (30 mL) and ensuing solution was heated at reflux under N2. After 2.5 h, the magnetically stirred solution was cooled to r.t. and CH2Cl2 (35 mL) and NaOAc (1.37 g, 16.6 mmol) and compound S6 (as a 15 mL aqueous solution) were added; the flask waswrapped in foil to exclude light. After 18 h, the pH of the aqueous phase was adjusted to ~9 with Na2CO3 (saturated aqueous solution) and the phases separated. The aqueous phase was further extracted with CH2Cl2 (4x 30 mL), the organic extracts were combined, dried (MgSO4) and passed through a plug ofsilica gel (CH2Cl2 elution) to provide pyrrole S7 (1.41 g, 7.20 mmol, 76% yield over 3 steps) as a colourless oil.

Molecular Weight:181.66
Hydrogen Bond Donor Count:2
Hydrogen Bond Acceptor Count:3
Rotatable Bond Count:6
Exact Mass:181.0869564
Monoisotopic Mass:181.0869564
Topological Polar Surface Area:52.3
Heavy Atom Count:11
Complexity:93.6
Covalently-Bonded Unit Count:2
Compound Is Canonicalized:Yes