I can't help you with your immediate inquiry, but have information that might help you tie back into the ancestors of your Friedrich Jennrich. My husband's ancestors tie back into a Friedrich Jennrich born 1655 in Gross Satspe, Pommern who married a Dorothea Molatske born 1659 also in Gross Satspe. they had a son Friedrich as well as our direct ancestor, a daughter named Sophia born 1698 in Gross Satspe. She married Adam Wendt and they had a son adam Alexamder born 1724 whose 2nd wife was also a Bruemmel (Eleanora) from Gross Satspe. So it seems that Jennrichs and Bruemmels from Gross Satspe were intertwined even as far back as the mid 1700s or earlier. You might be able to connect your recent Friedrich Jennrich to our ancestor born in 1655 in Gross Satspe. Hope this helps a bit.
B Friis