Context : Open star clusters older than \sim 1 Gyr are rare in the inner Galactic disc .
Still , they are objects that hold crucial information for probing the chemical evolution of these regions of the Milky Way .

Aims : We aim at increasing the number of old open clusters in the inner disc for which high-resolution metal abundances are available .
Here we report on NGC 4337 , which was recently discovered to be an old , inner disc open cluster .

Methods : We present the very first high-resolution spectroscopy of seven clump stars that are all cluster members .
We performed a detailed abundance analysis for them .

Results : We find that NGC 4337 is marginally more metal-rich than the Sun , with [ Fe/H ] =+0.12 \pm 0.05 .
The abundance ratios of \alpha -elements are generally solar .
At odds with recent studies on intermediate-age and old open clusters in the Galactic disc , Ba is under-abundant in NGC 4337 compared with the Sun .
Our analysis of the iron-peak elements ( Cr and Ni ) does not reveal anything anomalous .
Based on these results , we estimate the cluster age to be 1.6 ^ { +0.1 } _ { -0.1 } Gyr , and derive a reddening E ( B-V ) =0.23 \pm 0.05 , and an apparent distance modulus ( m - M ) _ { V } = 12.80 \pm 0.15 .
Its distance to the Galactic centre is 7.6 kpc .
With this distance and metallicity , NGC 4337 fits the metallicity gradient for the inner Galactic disc fairly well .

Conclusions : The age and metallicity we measured make NGC 4337 a twin of the well-known old open cluster NGC 752 .
The red clumps of these two clusters bear an amazing resemblance .
But the main sequence of NGC 752 is significantly more depleted in stars than that of NGC 4337 .
This would mean that NGC 752 is in a much more advanced dynamical stage , being on the verge of dissolving into the general Galactic field .
Our results make NGC 4337 an extremely interesting object for further studies of stellar evolution in the critical turn-off mass range 1.1-1.4 M _ { \odot } .