S. No.

N-R

Groups

1

Methyl

1617

1540

1326

541

488

2

Ethyl

1618

1543

1326

540

469

3

Propyl

1613

1552

1332

533

461

4

Butyl

1612

1564

1329

532

475

5

Pentyl

1615

1542

1332

549

496