diff --git a/jupyter_client/utils.py b/jupyter_client/utils.py
index 84a19616c..f9448841d 100644
--- a/jupyter_client/utils.py
+++ b/jupyter_client/utils.py
@@ -3,84 +3,10 @@
 - provides utility wrappers to run asynchronous functions in a blocking environment.
 - vendor functions from ipython_genutils that should be retired at some point.
 """
-import asyncio
-import atexit
-import inspect
 import os
-import threading
-from typing import Optional
-
-
-class _TaskRunner:
-    """A task runner that runs an asyncio event loop on a background thread."""
-
-    def __init__(self):
-        self.__io_loop: Optional[asyncio.AbstractEventLoop] = None
-        self.__runner_thread: Optional[threading.Thread] = None
-        self.__lock = threading.Lock()
-        atexit.register(self._close)
-
-    def _close(self):
-        if self.__io_loop:
-            self.__io_loop.stop()
-
-    def _runner(self):
-        loop = self.__io_loop
-        assert loop is not None
-        try:
-            loop.run_forever()
-        finally:
-            loop.close()
-
-    def run(self, coro):
-        """Synchronously run a coroutine on a background thread."""
-        with self.__lock:
-            name = f"{threading.current_thread().name} - runner"
-            if self.__io_loop is None:
-                self.__io_loop = asyncio.new_event_loop()
-                self.__runner_thread = threading.Thread(target=self._runner, daemon=True, name=name)
-                self.__runner_thread.start()
-        fut = asyncio.run_coroutine_threadsafe(coro, self.__io_loop)
-        return fut.result(None)
-
-
-_runner_map = {}
-_loop_map = {}
-
-
-def run_sync(coro):
-    def wrapped(*args, **kwargs):
-        name = threading.current_thread().name
-        inner = coro(*args, **kwargs)
-        try:
-            # If a loop is currently running in this thread,
-            # use a task runner.
-            asyncio.get_running_loop()
-            if name not in _runner_map:
-                _runner_map[name] = _TaskRunner()
-            return _runner_map[name].run(inner)
-        except RuntimeError:
-            pass
-
-        # Run the loop for this thread.
-        if name not in _loop_map:
-            _loop_map[name] = asyncio.new_event_loop()
-        loop = _loop_map[name]
-        return loop.run_until_complete(inner)
-
-    wrapped.__doc__ = coro.__doc__
-    return wrapped
-
-
-async def ensure_async(obj):
-    """Ensure a returned object is asynchronous.L
-
-    NOTE: This should only be used on methods of external classes,
-    not on a `self` method.
-    """
-    if inspect.isawaitable(obj):
-        return await obj
-    return obj
+
+from jupyter_core.utils import ensure_async  # noqa: F401
+from jupyter_core.utils import run_sync  # noqa: F401
 
 
 def _filefind(filename, path_dirs=None):
diff --git a/pyproject.toml b/pyproject.toml
index 37db68bc1..754f5e2fc 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -25,7 +25,7 @@ classifiers = [
 requires-python = ">=3.8"
 dependencies = [
     "importlib_metadata>=4.8.3;python_version<\"3.10\"",
-    "jupyter_core>=4.9.2",
+    "jupyter_core>=4.12,!=~5.0",
     "python-dateutil>=2.8.2",
     "pyzmq>=23.0",
     "tornado>=6.2",